diff --git a/easybuild/base/testing.py b/easybuild/base/testing.py
index ccef36a1ac..8acc604a11 100644
--- a/easybuild/base/testing.py
+++ b/easybuild/base/testing.py
@@ -139,6 +139,7 @@ def setUp(self):
 
         self.orig_sys_stdout = sys.stdout
         self.orig_sys_stderr = sys.stderr
+        self.stdout_std_err_buffers = []
 
     def convert_exception_to_str(self, err):
         """Convert an Exception instance to a string."""
@@ -182,6 +183,7 @@ def mock_stdout(self, enable):
         sys.stdout.flush()
         if enable:
             sys.stdout = StringIO()
+            self.stdout_std_err_buffers.append(sys.stdout)
         else:
             sys.stdout = self.orig_sys_stdout
 
@@ -190,6 +192,7 @@ def mock_stderr(self, enable):
         sys.stderr.flush()
         if enable:
             sys.stderr = StringIO()
+            self.stdout_std_err_buffers.append(sys.stderr)
         else:
             sys.stderr = self.orig_sys_stderr
 
@@ -235,4 +238,6 @@ def tearDown(self):
         """Cleanup after running a test."""
         self.mock_stdout(False)
         self.mock_stderr(False)
+        for buf in self.stdout_std_err_buffers:
+            buf.close()
         super().tearDown()
diff --git a/easybuild/tools/run.py b/easybuild/tools/run.py
index 0e9aa23cef..0778e937f8 100644
--- a/easybuild/tools/run.py
+++ b/easybuild/tools/run.py
@@ -573,8 +573,10 @@ def to_cmd_str(cmd):
         for line in iter(proc.stdout.readline, b''):
             _log.debug(f"Captured stdout: {line.decode(errors='ignore').rstrip()}")
             stdout += line
+        proc.stdout.close()
         if split_stderr:
             stderr += proc.stderr.read() or b''
+            proc.stderr.close()
     else:
         (stdout, stderr) = proc.communicate(input=stdin)
 
diff --git a/easybuild/tools/toolchain/toolchain.py b/easybuild/tools/toolchain/toolchain.py
index 6201699237..d7980b4e8e 100644
--- a/easybuild/tools/toolchain/toolchain.py
+++ b/easybuild/tools/toolchain/toolchain.py
@@ -658,7 +658,15 @@ def _load_toolchain_module(self, silent=False):
 
     def _load_dependencies_modules(self, silent=False):
         """Load modules for dependencies, and handle special cases like external modules."""
-        dep_mods = [dep['short_mod_name'] for dep in self.dependencies]
+        # For SYSTEM software we allow using dependencies from any toolchain so we need to use the full
+        # module name to allow loading them in the hierarchical MNS
+        is_system_toolchain = self.is_system_toolchain()
+
+        def get_module_name(dep):
+            key = 'full_mod_name' if is_system_toolchain and not dep[SYSTEM_TOOLCHAIN_NAME] else 'short_mod_name'
+            return dep[key]
+
+        dep_mods = [get_module_name(dep) for dep in self.dependencies]
 
         if self.dry_run:
             dry_run_msg("\nLoading modules for dependencies...\n", silent=silent)
@@ -667,7 +675,7 @@ def _load_dependencies_modules(self, silent=False):
 
             # load available modules for dependencies, simulate load for others
             for dep, dep_mod_exists in zip(self.dependencies, mods_exist):
-                mod_name = dep['short_mod_name']
+                mod_name = get_module_name(dep)
                 if dep_mod_exists:
                     self.modules_tool.load([mod_name])
                     dry_run_msg("module load %s" % mod_name, silent=silent)
@@ -683,7 +691,7 @@ def _load_dependencies_modules(self, silent=False):
             self.modules_tool.load(dep_mods)
 
             if self.dependencies:
-                build_dep_mods = [dep['short_mod_name'] for dep in self.dependencies if dep['build_only']]
+                build_dep_mods = [get_module_name(dep) for dep in self.dependencies if dep['build_only']]
                 if build_dep_mods:
                     trace_msg("loading modules for build dependencies:")
                     for dep_mod in build_dep_mods:
@@ -691,7 +699,7 @@ def _load_dependencies_modules(self, silent=False):
                 else:
                     trace_msg("(no build dependencies specified)")
 
-                run_dep_mods = [dep['short_mod_name'] for dep in self.dependencies if not dep['build_only']]
+                run_dep_mods = [get_module_name(dep) for dep in self.dependencies if not dep['build_only']]
                 if run_dep_mods:
                     trace_msg("loading modules for (runtime) dependencies:")
                     for dep_mod in run_dep_mods:
@@ -703,7 +711,7 @@ def _load_dependencies_modules(self, silent=False):
         self.modules.extend(dep_mods)
 
         # define $EBROOT* and $EBVERSION* for external modules, if metadata is available
-        for dep in [d for d in self.dependencies if d['external_module']]:
+        for dep in (d for d in self.dependencies if d['external_module']):
             mod_name = dep['full_mod_name']
             metadata = dep['external_module_metadata']
             self.log.debug("Metadata for external module %s: %s", mod_name, metadata)
@@ -752,7 +760,7 @@ def _verify_toolchain(self):
         self.log.debug("List of toolchain dependencies from toolchain module: %s", self.toolchain_dep_mods)
 
         # only retain names of toolchain elements, excluding toolchain name
-        toolchain_definition = {e for es in self.definition().values() for e in es if not e == self.name}
+        toolchain_definition = {e for es in self.definition().values() for e in es if e != self.name}
 
         # filter out optional toolchain elements if they're not used in the module
         for elem_name in toolchain_definition.copy():
@@ -862,7 +870,7 @@ def prepare(self, onlymod=None, deps=None, silent=False, loadmod=True,
         if deps is None:
             deps = []
         self.dependencies = self._check_dependencies(deps, check_modules=loadmod)
-        if not len(deps) == len(self.dependencies):
+        if len(deps) != len(self.dependencies):
             self.log.debug("dep %s (%s)" % (len(deps), deps))
             self.log.debug("tc.dep %s (%s)" % (len(self.dependencies), self.dependencies))
             raise EasyBuildError('Not all dependencies have a matching toolchain version')
diff --git a/test/framework/modules.py b/test/framework/modules.py
index b69bb69c3e..ca4a55bc21 100644
--- a/test/framework/modules.py
+++ b/test/framework/modules.py
@@ -54,7 +54,7 @@
 
 
 # number of modules included for testing purposes
-TEST_MODULES_COUNT = 118
+TEST_MODULES_COUNT = 119
 
 
 class ModulesTest(EnhancedTestCase):
diff --git a/test/framework/modules/ncurses/6.4-GCCcore-12.3.0 b/test/framework/modules/ncurses/6.4-GCCcore-12.3.0
new file mode 100644
index 0000000000..b1c469d008
--- /dev/null
+++ b/test/framework/modules/ncurses/6.4-GCCcore-12.3.0
@@ -0,0 +1,36 @@
+#%Module
+proc ModulesHelp { } {
+    puts stderr {
+
+Description
+===========
+The Ncurses (new curses) library is a free software emulation of curses in
+ System V Release 4.0, and more. It uses Terminfo format, supports pads and
+ color and multiple highlights and forms characters and function-key mapping,
+ and has all the other SYSV-curses enhancements over BSD Curses.
+
+
+More information
+================
+ - Homepage: https://www.gnu.org/software/ncurses/
+    }
+}
+
+module-whatis {Description:
+ The Ncurses (new curses) library is a free software emulation of curses in
+ System V Release 4.0, and more. It uses Terminfo format, supports pads and
+ color and multiple highlights and forms characters and function-key mapping,
+ and has all the other SYSV-curses enhancements over BSD Curses.
+}
+module-whatis {Homepage: https://www.gnu.org/software/ncurses/}
+module-whatis {URL: https://www.gnu.org/software/ncurses/}
+
+set root /tmp/software/ncurses/6.4-GCCcore-12.3.0
+
+conflict ncurses
+
+setenv	EBROOTNCURSES		"$root"
+setenv	EBVERSIONNCURSES		"6.4"
+setenv	EBDEVELNCURSES		"$root/easybuild/Compiler-GCCcore-12.3.0-ncurses-6.4-easybuild-devel"
+
+# Built with EasyBuild version 5.1.2.dev0-r5819168038d7bd74810f38f75acfced9fb41870e
diff --git a/test/framework/toy_build.py b/test/framework/toy_build.py
index 973f76ac03..1f982af09d 100644
--- a/test/framework/toy_build.py
+++ b/test/framework/toy_build.py
@@ -63,6 +63,11 @@
 from easybuild.tools.systemtools import get_shared_lib_ext
 from easybuild.tools.version import VERSION as EASYBUILD_VERSION
 
+TEST_DIR = os.path.dirname(os.path.abspath(__file__))
+TEST_ECS_DIR = os.path.join(TEST_DIR, 'easyconfigs', 'test_ecs')
+TOY_EC = os.path.join(TEST_ECS_DIR, 't', 'toy', 'toy-0.0.eb')
+TOY_EC_TXT: str = read_file(TOY_EC)
+
 
 class ToyBuildTest(EnhancedTestCase):
     """Toy build unit test."""
@@ -165,13 +170,13 @@ def _test_toy_build(self, extra_args=None, ec_file=None, tmpdir=None, verify=Tru
             extra_args = []
         test_readme = False
         if ec_file is None:
-            ec_file = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
+            ec_file = TOY_EC
             test_readme = True
         full_ver = '0.0%s' % versionsuffix
         args = [
             ec_file,
             '--unittest-file=%s' % self.logfile,
-            '--robot=%s' % os.pathsep.join([self.test_buildpath, os.path.dirname(__file__)]),
+            '--robot=%s' % os.pathsep.join([self.test_buildpath, TEST_DIR]),
         ]
         if debug:
             args.append('--debug')
@@ -259,8 +264,7 @@ def test_toy_broken(self):
         """Test deliberately broken toy build."""
         tmpdir = tempfile.mkdtemp()
         broken_toy_ec = os.path.join(tmpdir, "toy-broken.eb")
-        toy_ec_file = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        broken_toy_ec_txt = read_file(toy_ec_file)
+        broken_toy_ec_txt = TOY_EC_TXT
         broken_toy_ec_txt += "checksums = ['clearywrongSHA256checksumoflength64-0123456789012345678901234567']"
         write_file(broken_toy_ec, broken_toy_ec_txt)
         error_regex = "Checksum verification .* failed"
@@ -288,13 +292,10 @@ def test_toy_broken_copy_log_build_dir(self):
         Test whether log files and the build directory are copied to a permanent location
         after a failed installation.
         """
-        toy_ec = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec)
-
         test_ec_txt = re.sub(
             r'toy-0\.0_fix-silly-typo-in-printf-statement\.patch',
             r'toy-0.0_add-bug.patch',
-            toy_ec_txt
+            TOY_EC_TXT
         )
         test_ec = os.path.join(self.test_prefix, 'toy-0.0-buggy.eb')
         write_file(test_ec, test_ec_txt)
@@ -361,9 +362,8 @@ def test_toy_broken_copy_log_build_dir(self):
 
     def test_toy_tweaked(self):
         """Test toy build with tweaked easyconfig, for testing extra easyconfig parameters."""
-        test_ecs_dir = os.path.join(os.path.abspath(os.path.dirname(__file__)), 'easyconfigs')
         ec_file = os.path.join(self.test_buildpath, 'toy-0.0-tweaked.eb')
-        shutil.copy2(os.path.join(test_ecs_dir, 'test_ecs', 't', 'toy', 'toy-0.0.eb'), ec_file)
+        shutil.copy2(TOY_EC, ec_file)
 
         modloadmsg = 'THANKS FOR LOADING ME\\nI AM %(name)s v%(version)s'
         modloadmsg_regex_tcl = r'THANKS.*\n\s*I AM toy v0.0\n\s*"'
@@ -462,9 +462,8 @@ def test_toy_tweaked(self):
 
     def test_toy_buggy_easyblock(self):
         """Test build using a buggy/broken easyblock, make sure a traceback is reported."""
-        ec_file = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
         kwargs = {
-            'ec_file': ec_file,
+            'ec_file': TOY_EC,
             'extra_args': ['--easyblock=EB_toy_buggy'],
             'raise_error': True,
             'verify': False,
@@ -477,14 +476,14 @@ def test_toy_build_formatv2(self):
         """Perform a toy build (format v2)."""
         # set $MODULEPATH such that modules for specified dependencies are found
         modulepath = os.environ.get('MODULEPATH')
-        os.environ['MODULEPATH'] = os.path.abspath(os.path.join(os.path.dirname(__file__), 'modules'))
+        os.environ['MODULEPATH'] = os.path.join(TEST_DIR, 'modules')
 
         args = [
-            os.path.join(os.path.dirname(__file__), 'easyconfigs', 'v2.0', 'toy.eb'),
+            os.path.join(TEST_DIR, 'easyconfigs', 'v2.0', 'toy.eb'),
             '--debug',
             '--unittest-file=%s' % self.logfile,
             '--force',
-            '--robot=%s' % os.pathsep.join([self.test_buildpath, os.path.dirname(__file__)]),
+            '--robot=%s' % os.pathsep.join([self.test_buildpath, TEST_DIR]),
             '--software-version=0.0',
             '--toolchain=system,system',
             '--experimental',
@@ -508,8 +507,7 @@ def test_toy_build_with_blocks(self):
         # note get_paths_for expects easybuild/easyconfigs subdir
         ecs_path = os.path.join(tmpdir, "easybuild", "easyconfigs")
         os.makedirs(ecs_path)
-        test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        shutil.copy2(os.path.join(test_ecs, 't', 'toy', 'toy-0.0-multiple.eb'), ecs_path)
+        shutil.copy2(os.path.join(TEST_ECS_DIR, 't', 'toy', 'toy-0.0-multiple.eb'), ecs_path)
         sys.path.append(tmpdir)
 
         args = [
@@ -546,11 +544,11 @@ def test_toy_build_formatv2_sections(self):
 
         for version, specs in versions.items():
             args = [
-                os.path.join(os.path.dirname(__file__), 'easyconfigs', 'v2.0', 'toy-with-sections.eb'),
+                os.path.join(TEST_DIR, 'easyconfigs', 'v2.0', 'toy-with-sections.eb'),
                 '--debug',
                 '--unittest-file=%s' % self.logfile,
                 '--force',
-                '--robot=%s' % os.pathsep.join([self.test_buildpath, os.path.dirname(__file__)]),
+                '--robot=%s' % os.pathsep.join([self.test_buildpath, TEST_DIR]),
                 '--software-version=%s' % version,
                 '--toolchain=system,system',
                 '--experimental',
@@ -566,9 +564,8 @@ def test_toy_download_sources(self):
         """Test toy build with sources that still need to be 'downloaded'."""
         tmpdir = tempfile.mkdtemp()
         # copy toy easyconfig file, and append source_urls to it
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        shutil.copy2(os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb'), tmpdir)
-        source_url = os.path.join(topdir, 'sandbox', 'sources', 'toy')
+        shutil.copy2(TOY_EC, tmpdir)
+        source_url = os.path.join(TEST_DIR, 'sandbox', 'sources', 'toy')
         ec_file = os.path.join(tmpdir, 'toy-0.0.eb')
         write_file(ec_file, '\nsource_urls = ["file://%s"]\n' % source_url, append=True)
 
@@ -594,8 +591,7 @@ def test_toy_download_sources(self):
 
     def test_toy_permissions(self):
         """Test toy build with custom umask settings."""
-        toy_ec_file = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        test_ec_txt = read_file(toy_ec_file)
+        test_ec_txt = TOY_EC_TXT
 
         # remove exec perms on bin subdirectory for others, to check whether correct dir permissions are set
         test_ec_txt += "\npostinstallcmds += ['chmod o-x %(installdir)s/bin']"
@@ -703,8 +699,7 @@ def test_toy_permissions_installdir(self):
         # set umask hard to verify default reliably
         orig_umask = os.umask(0o022)
 
-        toy_ec = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         # take away read permissions, to check whether they are correctly restored by EasyBuild after installation
         test_ec_txt += "\npostinstallcmds += ['chmod -R og-r %(installdir)s']"
 
@@ -830,7 +825,6 @@ def test_toy_group_check(self):
         self.assertEqual(res.exit_code, 0, "Failed to select group to use in test")
         group_name = res.output.split(' ')[0].strip()
 
-        toy_ec = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         args = [
             test_ec,
@@ -841,9 +835,9 @@ def test_toy_group_check(self):
         for group in [group_name, (group_name, "Hey, you're not in the '%s' group!" % group_name)]:
 
             if isinstance(group, str):
-                write_file(test_ec, read_file(toy_ec) + "\ngroup = '%s'\n" % group)
+                write_file(test_ec, TOY_EC_TXT + "\ngroup = '%s'\n" % group)
             else:
-                write_file(test_ec, read_file(toy_ec) + "\ngroup = %s\n" % str(group))
+                write_file(test_ec, TOY_EC_TXT + "\ngroup = %s\n" % str(group))
 
             self.mock_stdout(True)
             outtxt = self.eb_main(args, logfile=dummylogfn, do_build=True, raise_error=True, raise_systemexit=True)
@@ -895,7 +889,7 @@ def test_toy_group_check(self):
             else:
                 self.fail("Unknown module syntax: %s" % get_module_syntax())
 
-        write_file(test_ec, read_file(toy_ec) + "\ngroup = ('%s', 'custom message', 'extra item')\n" % group_name)
+        write_file(test_ec, TOY_EC_TXT + "\ngroup = ('%s', 'custom message', 'extra item')\n" % group_name)
         self.assertErrorRegex(SystemExit, '.*', self.eb_main, args, do_build=True,
                               raise_error=True, raise_systemexit=True)
 
@@ -903,8 +897,7 @@ def test_allow_system_deps(self):
         """Test allow_system_deps easyconfig parameter."""
         tmpdir = tempfile.mkdtemp()
         # copy toy easyconfig file, and append source_urls to it
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        shutil.copy2(os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb'), tmpdir)
+        shutil.copy2(TOY_EC, tmpdir)
         ec_file = os.path.join(tmpdir, 'toy-0.0.eb')
         write_file(ec_file, "\nallow_system_deps = [('Python', SYS_PYTHON_VERSION)]\n", append=True)
         with self.mocked_stdout_stderr():
@@ -913,17 +906,15 @@ def test_allow_system_deps(self):
 
     def test_toy_hierarchical(self):
         """Test toy build under example hierarchical module naming scheme."""
-
-        test_easyconfigs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
         self.setup_hierarchical_modules()
         mod_prefix = os.path.join(self.test_installpath, 'modules', 'all')
 
         args = [
-            os.path.join(test_easyconfigs, 't', 'toy', 'toy-0.0.eb'),
+            os.path.join(TOY_EC),
             '--debug',
             '--unittest-file=%s' % self.logfile,
             '--force',
-            '--robot=%s' % test_easyconfigs,
+            '--robot=%s' % TEST_ECS_DIR,
             '--module-naming-scheme=HierarchicalMNS',
         ]
 
@@ -1077,7 +1068,7 @@ def test_toy_hierarchical(self):
         if get_module_syntax() == 'Lua':
             gompi_module_path += '.lua'
 
-        args[0] = os.path.join(test_easyconfigs, 'g', 'gompi', 'gompi-2018a.eb')
+        args[0] = os.path.join(TEST_ECS_DIR, 'g', 'gompi', 'gompi-2018a.eb')
         self.modtool.purge()
         with self.mocked_stdout_stderr():
             self.eb_main(args, logfile=self.dummylogfn, do_build=True, verbose=True, raise_error=True)
@@ -1093,7 +1084,6 @@ def test_toy_hierarchical_subdir_user_modules(self):
         mkdir(home)
         os.environ['HOME'] = home
 
-        test_easyconfigs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
         self.setup_hierarchical_modules()
         mod_prefix = os.path.join(self.test_installpath, 'modules', 'all')
 
@@ -1119,7 +1109,7 @@ def test_toy_hierarchical_subdir_user_modules(self):
         write_file(openmpi_mod, extra_modtxt, append=True)
 
         args = [
-            os.path.join(test_easyconfigs, 't', 'toy', 'toy-0.0-gompi-2018a.eb'),
+            os.path.join(TEST_ECS_DIR, 't', 'toy', 'toy-0.0-gompi-2018a.eb'),
             '--installpath=%s' % home,
             '--unittest-file=%s' % self.logfile,
             '--force',
@@ -1201,9 +1191,8 @@ def test_toy_hierarchical_subdir_user_modules(self):
 
     def test_toy_advanced(self):
         """Test toy build with extensions and non-system toolchain."""
-        test_dir = os.path.abspath(os.path.dirname(__file__))
-        os.environ['MODULEPATH'] = os.path.join(test_dir, 'modules')
-        test_ec = os.path.join(test_dir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0-gompi-2018a-test.eb')
+        os.environ['MODULEPATH'] = os.path.join(TEST_DIR, 'modules')
+        test_ec = os.path.join(TEST_ECS_DIR, 't', 'toy', 'toy-0.0-gompi-2018a-test.eb')
         with self.mocked_stdout_stderr():
             self._test_toy_build(ec_file=test_ec, versionsuffix='-gompi-2018a-test', extra_args=['--debug'])
 
@@ -1232,9 +1221,8 @@ def test_toy_advanced_filter_deps(self):
         """Test toy build with extensions, and filtered build dependency."""
         # test case for bug https://github.com/easybuilders/easybuild-framework/pull/2515
 
-        test_dir = os.path.abspath(os.path.dirname(__file__))
-        os.environ['MODULEPATH'] = os.path.join(test_dir, 'modules')
-        toy_ec = os.path.join(test_dir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0-gompi-2018a-test.eb')
+        os.environ['MODULEPATH'] = os.path.join(TEST_DIR, 'modules')
+        toy_ec = os.path.join(TEST_ECS_DIR, 't', 'toy', 'toy-0.0-gompi-2018a-test.eb')
 
         toy_ec_txt = read_file(toy_ec)
         # add FFTW as build dependency, just to filter it out again
@@ -1253,10 +1241,8 @@ def test_toy_advanced_filter_deps(self):
 
     def test_toy_hidden_cmdline(self):
         """Test installing a hidden module using the '--hidden' command line option."""
-        test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        ec_file = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
         with self.mocked_stdout_stderr():
-            self._test_toy_build(ec_file=ec_file, extra_args=['--hidden'], verify=False)
+            self._test_toy_build(ec_file=TOY_EC, extra_args=['--hidden'], verify=False)
         # module file is hidden
         toy_module = os.path.join(self.test_installpath, 'modules', 'all', 'toy', '.0.0')
         if get_module_syntax() == 'Lua':
@@ -1269,9 +1255,7 @@ def test_toy_hidden_cmdline(self):
     def test_toy_hidden_easyconfig(self):
         """Test installing a hidden module using the 'hidden = True' easyconfig parameter."""
         # copy toy easyconfig file, and add hiding option to it
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        ec_file = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        shutil.copy2(ec_file, self.test_prefix)
+        shutil.copy2(TOY_EC, self.test_prefix)
         ec_file = os.path.join(self.test_prefix, 'toy-0.0.eb')
         write_file(ec_file, "\nhidden = True\n", append=True)
         with self.mocked_stdout_stderr():
@@ -1290,10 +1274,8 @@ def test_module_filepath_tweaking(self):
         mns_path = "easybuild.tools.module_naming_scheme.test_module_naming_scheme"
         __import__(mns_path, globals(), locals(), [''])
 
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        eb_file = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
         args = [
-            eb_file,
+            TOY_EC,
             '--force',
             '--debug',
             '--suffix-modules-path=foobarbaz',
@@ -1348,15 +1330,11 @@ def test_toy_patches(self):
 
     def test_toy_extension_patches_postinstallcmds(self):
         """Test install toy that includes extensions with patches and postinstallcmds."""
-        test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec)
-
         # create file that we'll copy via 'patches'
         write_file(os.path.join(self.test_prefix, 'test.txt'), 'test123')
 
         test_ec = os.path.join(self.test_prefix, 'test.eb')
-        test_ec_txt = f"{toy_ec_txt}\n" + textwrap.dedent("""
+        test_ec_txt = f"{TOY_EC_TXT}\n" + textwrap.dedent("""
             exts_defaultclass = "DummyExtension"
             exts_list = [
                ("bar", "0.0", {
@@ -1406,11 +1384,6 @@ def test_toy_extension_patches_postinstallcmds(self):
 
     def test_toy_extension_sources(self):
         """Test install toy that includes extensions with 'sources' spec (as single-item list)."""
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        test_ecs = os.path.join(topdir, 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec)
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
 
         bar_sources_specs = [
@@ -1422,7 +1395,7 @@ def test_toy_extension_sources(self):
 
             # test use of single-element list in 'sources' with just the filename
             test_ec_txt = '\n'.join([
-                toy_ec_txt,
+                TOY_EC_TXT,
                 'exts_defaultclass = "DummyExtension"',
                 'exts_list = [',
                 '   ("bar", "0.0", {',
@@ -1436,7 +1409,7 @@ def test_toy_extension_sources(self):
 
             # copy bar-0.0.tar.gz to <tmpdir>/bar-0.0-local.tar.gz, to be used below
             test_source_path = os.path.join(self.test_prefix, 'sources')
-            toy_ext_sources = os.path.join(topdir, 'sandbox', 'sources', 'toy', 'extensions')
+            toy_ext_sources = os.path.join(TEST_DIR, 'sandbox', 'sources', 'toy', 'extensions')
 
             bar_source = os.path.join(toy_ext_sources, 'bar-0.0.tar.gz')
             copy_file(bar_source, os.path.join(test_source_path, 'bar-0.0-local.tar.gz'))
@@ -1450,7 +1423,7 @@ def test_toy_extension_sources(self):
             bar_sources_spec = bar_sources_spec.replace('bar-%(version)s.tar.gz', 'bar-0.0-local.tar.gz')
 
             test_ec_txt = '\n'.join([
-                toy_ec_txt,
+                TOY_EC_TXT,
                 'exts_defaultclass = "DummyExtension"',
                 'exts_list = [',
                 '   ("bar", "0.0", {',
@@ -1466,7 +1439,7 @@ def test_toy_extension_sources(self):
 
             # check that checksums are picked up and verified
             test_ec_txt = '\n'.join([
-                toy_ec_txt,
+                TOY_EC_TXT,
                 'exts_defaultclass = "DummyExtension"',
                 'exts_list = [',
                 '   ("bar", "0.0", {',
@@ -1490,7 +1463,7 @@ def test_toy_extension_sources(self):
 
             # test again with correct checksum for bar-0.0.tar.gz, but faulty checksum for patch file
             test_ec_txt = '\n'.join([
-                toy_ec_txt,
+                TOY_EC_TXT,
                 'exts_defaultclass = "DummyExtension"',
                 'exts_list = [',
                 '   ("bar", "0.0", {',
@@ -1514,7 +1487,7 @@ def test_toy_extension_sources(self):
 
             # test again with correct checksums
             test_ec_txt = '\n'.join([
-                toy_ec_txt,
+                TOY_EC_TXT,
                 'exts_defaultclass = "DummyExtension"',
                 'exts_list = [',
                 '   ("bar", "0.0", {',
@@ -1534,13 +1507,9 @@ def test_toy_extension_sources(self):
 
     def test_toy_extension_extract_cmd(self):
         """Test for custom extract_cmd specified for an extension."""
-        test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec)
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         test_ec_txt = '\n'.join([
-            toy_ec_txt,
+            TOY_EC_TXT,
             'exts_defaultclass = "DummyExtension"',
             'exts_list = [',
             '   ("bar", "0.0", {',
@@ -1563,10 +1532,6 @@ def test_toy_extension_extract_cmd(self):
 
     def test_toy_extension_sources_git_config(self):
         """Test install toy that includes extensions with 'sources' spec including 'git_config'."""
-        test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec)
-
         # Tar-ball which should be created via 'git_config', and one file
         ext_tgz = 'exts-git.tar.gz'
         ext_tarball = os.path.join(self.test_sourcepath, 't', 'toy', ext_tgz)
@@ -1578,7 +1543,7 @@ def test_toy_extension_sources_git_config(self):
 
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         test_ec_txt = '\n'.join([
-            toy_ec_txt,
+            TOY_EC_TXT,
             'prebuildopts = "echo \\\"%s\\\" > %s && ",' % (ext_code, ext_cfile),
             'exts_defaultclass = "DummyExtension"',
             'exts_list = [',
@@ -1741,8 +1706,7 @@ def test_toy_module_fulltxt(self):
     def test_external_dependencies(self):
         """Test specifying external (build) dependencies."""
 
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        ectxt = read_file(os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0-deps.eb'))
+        ectxt = read_file(os.path.join(TEST_ECS_DIR, 't', 'toy', 'toy-0.0-deps.eb'))
         toy_ec = os.path.join(self.test_prefix, 'toy-0.0-external-deps.eb')
 
         # just specify some of the test modules we ship, doesn't matter where they come from
@@ -1804,19 +1768,18 @@ def test_external_dependencies(self):
 
     def test_module_only(self):
         """Test use of --module-only."""
-        ec_files_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        ec_file = os.path.join(ec_files_path, 't', 'toy', 'toy-0.0-deps.eb')
+        ec_file = os.path.join(TEST_ECS_DIR, 't', 'toy', 'toy-0.0-deps.eb')
         toy_mod = os.path.join(self.test_installpath, 'modules', 'all', 'toy', '0.0-deps')
 
         # only consider provided test modules
-        self.reset_modulepath([os.path.join(os.path.dirname(os.path.abspath(__file__)), 'modules')])
+        self.reset_modulepath([os.path.join(TEST_DIR, 'modules')])
 
         # sanity check fails without --force if software is not installed yet
         common_args = [
             ec_file,
             '--debug',
             '--unittest-file=%s' % self.logfile,
-            '--robot=%s' % ec_files_path,
+            '--robot=%s' % TEST_ECS_DIR,
             '--module-syntax=Tcl',
         ]
         args = common_args + ['--module-only']
@@ -1931,15 +1894,12 @@ def test_module_only_extensions(self):
         Sanity check should catch problems with extensions,
         extensions can be skipped using --skip-exts.
         """
-        topdir = os.path.abspath(os.path.dirname(__file__))
-        toy_ec = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-
         toy_mod = os.path.join(self.test_installpath, 'modules', 'all', 'toy', '0.0')
         if get_module_syntax() == 'Lua':
             toy_mod += '.lua'
 
         test_ec = os.path.join(self.test_prefix, 'test.ec')
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += '\n' + '\n'.join([
             "sanity_check_commands = ['barbar', 'toy']",
             "sanity_check_paths = {'files': ['bin/barbar', 'bin/toy'], 'dirs': ['bin']}",
@@ -2003,15 +1963,12 @@ def test_toy_exts_parallel(self):
         """
         Test parallel installation of extensions (--parallel-extensions-install)
         """
-        topdir = os.path.abspath(os.path.dirname(__file__))
-        toy_ec = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-
         toy_mod = os.path.join(self.test_installpath, 'modules', 'all', 'toy', '0.0')
         if get_module_syntax() == 'Lua':
             toy_mod += '.lua'
 
         test_ec = os.path.join(self.test_prefix, 'test.eb')
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += '\n' + '\n'.join([
             "exts_defaultclass = 'DummyExtension'",
             "exts_list = [",
@@ -2065,7 +2022,7 @@ def test_toy_exts_parallel(self):
 
         # check behaviour when using Toy_Extension easyblock that doesn't implement required_deps method;
         # framework should fall back to installing extensions sequentially
-        toy_ext_eb = os.path.join(topdir, 'sandbox', 'easybuild', 'easyblocks', 'generic', 'toy_extension.py')
+        toy_ext_eb = os.path.join(TEST_DIR, 'sandbox', 'easybuild', 'easyblocks', 'generic', 'toy_extension.py')
         copy_file(toy_ext_eb, self.test_prefix)
         toy_ext_eb = os.path.join(self.test_prefix, 'toy_extension.py')
         toy_ext_eb_txt = read_file(toy_ext_eb)
@@ -2093,8 +2050,7 @@ def test_toy_exts_parallel(self):
     def test_backup_modules(self):
         """Test use of backing up of modules with --module-only."""
 
-        ec_files_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        ec_file = os.path.join(ec_files_path, 't', 'toy', 'toy-0.0-deps.eb')
+        ec_file = os.path.join(TEST_ECS_DIR, 't', 'toy', 'toy-0.0-deps.eb')
         toy_mod = os.path.join(self.test_installpath, 'modules', 'all', 'toy', '0.0-deps')
         toy_mod_dir, toy_mod_fn = os.path.split(toy_mod)
 
@@ -2102,7 +2058,7 @@ def test_backup_modules(self):
             ec_file,
             '--debug',
             '--unittest-file=%s' % self.logfile,
-            '--robot=%s' % ec_files_path,
+            '--robot=%s' % TEST_ECS_DIR,
             '--force',
             '--disable-cleanup-tmpdir'
         ]
@@ -2387,13 +2343,9 @@ def test_reproducibility(self):
     def test_reproducibility_ext_easyblocks(self):
         """Test toy build produces expected reproducibility files also when extensions are used"""
 
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        toy_ec_file = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec_file)
-
         ec1 = os.path.join(self.test_prefix, 'toy1.eb')
         ec1_txt = '\n'.join([
-            toy_ec_txt,
+            TOY_EC_TXT,
             "exts_defaultclass = 'DummyExtension'",
             "exts_list = [('barbar', '1.2', {'start_dir': 'src'})]",
             "",
@@ -2428,13 +2380,9 @@ def test_reproducibility_ext_easyblocks(self):
     def test_toy_toy(self):
         """Test building two easyconfigs in a single go, with one depending on the other."""
 
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        toy_ec_file = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec_file)
-
         ec1 = os.path.join(self.test_prefix, 'toy1.eb')
         ec1_txt = '\n'.join([
-            toy_ec_txt,
+            TOY_EC_TXT,
             "versionsuffix = '-one'",
         ])
         write_file(ec1, ec1_txt)
@@ -2443,7 +2391,7 @@ def test_toy_toy(self):
         # name ('toy2' instead of 'toy')
         ec2 = os.path.join(self.test_prefix, 'toy2.eb')
         ec2_txt = '\n'.join([
-            toy_ec_txt,
+            TOY_EC_TXT,
             "name = 'toy2'",
             "easyblock = 'EB_toy'",
             "sources = ['toy/toy-0.0.tar.gz']",
@@ -2494,13 +2442,10 @@ def test_toy_sanity_check_commands(self):
 
         self.setup_hierarchical_modules()
 
-        test_easyconfigs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec_txt = read_file(os.path.join(test_easyconfigs, 't', 'toy', 'toy-0.0.eb'))
-
         out_file = os.path.join(self.test_prefix, 'out.txt')
 
         toy_ec_txt = '\n'.join([
-            toy_ec_txt,
+            TOY_EC_TXT,
             "toolchain = {'name': 'foss', 'version': '2018a'}",
             # specially construct (sort of senseless) sanity check commands,
             # that will fail if the corresponding modules are not loaded
@@ -2527,7 +2472,7 @@ def test_toy_sanity_check_commands(self):
             '--debug',
             '--unittest-file=%s' % self.logfile,
             '--force',
-            '--robot=%s' % test_easyconfigs,
+            '--robot=%s' % TEST_ECS_DIR,
             '--module-naming-scheme=HierarchicalMNS',
         ]
         with self.mocked_stdout_stderr():
@@ -2549,12 +2494,8 @@ def test_toy_sanity_check_commands(self):
 
     def test_sanity_check_paths_lib64(self):
         """Test whether fallback in sanity check for lib64/ equivalents of library files works."""
-        test_ecs_dir = os.path.join(os.path.abspath(os.path.dirname(__file__)), 'easyconfigs')
-        ec_file = os.path.join(test_ecs_dir, 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        ectxt = read_file(ec_file)
-
         # modify test easyconfig: move lib/libtoy.a to lib64/libtoy.a
-        ectxt = re.sub(r"\s*'files'.*", "'files': ['bin/toy', ('lib/libtoy.a', 'lib/libfoo.a')],", ectxt)
+        ectxt = re.sub(r"\s*'files'.*", "'files': ['bin/toy', ('lib/libtoy.a', 'lib/libfoo.a')],", TOY_EC_TXT)
         postinstallcmd = ' && '.join([
             # remove lib64 symlink (if it's there)
             "rm -f %(installdir)s/lib64",
@@ -2594,8 +2535,7 @@ def test_sanity_check_paths_lib64(self):
             self._test_toy_build(ec_file=test_ec, extra_args=['--disable-lib64-lib-symlink'], raise_error=True)
 
         # also check other way around (lib64 -> lib)
-        ectxt = read_file(ec_file)
-        ectxt = re.sub(r"\s*'files'.*", "'files': ['bin/toy', 'lib64/libtoy.a'],", ectxt)
+        ectxt = re.sub(r"\s*'files'.*", "'files': ['bin/toy', 'lib64/libtoy.a'],", TOY_EC_TXT)
         write_file(test_ec, ectxt)
 
         # sanity check fails if lib64 fallback in sanity check is disabled, since lib64/libtoy.a is not there
@@ -2624,8 +2564,7 @@ def test_sanity_check_paths_lib64(self):
             self._test_toy_build(ec_file=test_ec, extra_args=['--disable-lib64-lib-symlink'], raise_error=True)
 
         # check whether fallback works for files that's more than 1 subdir deep
-        ectxt = read_file(ec_file)
-        ectxt = re.sub(r"\s*'files'.*", "'files': ['bin/toy', 'lib/test/libtoy.a'],", ectxt)
+        ectxt = re.sub(r"\s*'files'.*", "'files': ['bin/toy', 'lib/test/libtoy.a'],", TOY_EC_TXT)
         postinstallcmd = "mkdir -p %(installdir)s/lib64/test && "
         postinstallcmd += "mv %(installdir)s/lib/libtoy.a %(installdir)s/lib64/test/libtoy.a"
         ectxt = re.sub("postinstallcmds.*", "postinstallcmds = ['%s']" % postinstallcmd, ectxt)
@@ -2641,21 +2580,17 @@ def test_toy_build_enhanced_sanity_check(self):
         if 'easybuild.easyblocks.toy' in sys.modules:
             del sys.modules['easybuild.easyblocks.toy']
 
-        test_dir = os.path.join(os.path.abspath(os.path.dirname(__file__)))
-        toy_ec = os.path.join(test_dir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec)
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
 
         # get rid of custom sanity check paths in test easyconfig
         regex = re.compile(r'^sanity_check_paths\s*=\s*{[^}]+}', re.M)
-        test_ec_txt = regex.sub('', toy_ec_txt)
+        test_ec_txt = regex.sub('', TOY_EC_TXT)
         write_file(test_ec, test_ec_txt)
 
         self.assertNotIn('sanity_check_', test_ec_txt)
 
         # create custom easyblock for toy that has a custom sanity_check_step
-        toy_easyblock = os.path.join(test_dir, 'sandbox', 'easybuild', 'easyblocks', 't', 'toy.py')
+        toy_easyblock = os.path.join(TEST_DIR, 'sandbox', 'easybuild', 'easyblocks', 't', 'toy.py')
 
         toy_easyblock_txt = read_file(toy_easyblock)
 
@@ -2805,22 +2740,18 @@ def test_toy_build_enhanced_sanity_check_templated_multi_dep(self):
         if 'easybuild.easyblocks.toy' in sys.modules:
             del sys.modules['easybuild.easyblocks.toy']
 
-        test_dir = os.path.join(os.path.abspath(os.path.dirname(__file__)))
-        toy_ec = os.path.join(test_dir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec)
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
 
         # get rid of custom sanity check paths in test easyconfig
         regex = re.compile(r'^sanity_check_paths\s*=\s*{[^}]+}', re.M)
-        test_ec_txt = regex.sub('', toy_ec_txt)
+        test_ec_txt = regex.sub('', TOY_EC_TXT)
         self.assertNotIn('sanity_check_', test_ec_txt)
 
         test_ec_txt += "\nmulti_deps = {'Python': ['3.7.2', '2.7.15']}"
         write_file(test_ec, test_ec_txt)
 
         # create custom easyblock for toy that has a custom sanity_check_step
-        toy_easyblock = os.path.join(test_dir, 'sandbox', 'easybuild', 'easyblocks', 't', 'toy.py')
+        toy_easyblock = os.path.join(TEST_DIR, 'sandbox', 'easybuild', 'easyblocks', 't', 'toy.py')
 
         toy_easyblock_txt = read_file(toy_easyblock)
 
@@ -2893,9 +2824,8 @@ def sanity_check_step(self):
     def test_toy_dumped_easyconfig(self):
         """ Test dumping of file in eb_filerepo in both .eb format """
         filename = 'toy-0.0'
-        test_ecs_dir = os.path.join(os.path.abspath(os.path.dirname(__file__)), 'easyconfigs')
         paths = [
-            os.path.join(test_ecs_dir, 'test_ecs', 't', 'toy', '%s.eb' % filename),
+            os.path.join(TEST_ECS_DIR, 't', 'toy', '%s.eb' % filename),
         ]
 
         for path in paths:
@@ -2945,8 +2875,7 @@ def test_toy_filter_env_vars(self):
 
     def test_toy_iter(self):
         """Test toy build that involves iterating over buildopts."""
-        topdir = os.path.abspath(os.path.dirname(__file__))
-        toy_ec = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0-iter.eb')
+        toy_ec = os.path.join(TEST_ECS_DIR, 't', 'toy', 'toy-0.0-iter.eb')
 
         expected_buildopts = ['', '-O2; mv %(name)s toy_O2_$EBVERSIONGCC', '-O1; mv %(name)s toy_O1_$EBVERSIONGCC']
 
@@ -2966,7 +2895,7 @@ def test_toy_rpath(self):
         # find_eb_script function used to find rpath_args.py requires that location where easybuild/scripts
         # resides is listed in sys.path via absolute path;
         # this is only needed to make this test pass when it's being called from that same location...
-        top_path = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+        top_path = os.path.dirname(os.path.dirname(TEST_DIR))
         sys.path.insert(0, top_path)
 
         def grab_gcc_rpath_wrapper_args():
@@ -3040,8 +2969,7 @@ def grab_gcc_rpath_wrapper_args():
 
         # test use of rpath toolchain option with SYSTEM and gompi 2018b toolchains
         for toolchain in ['', '-gompi-2018a']:
-            test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-            toy_ec_txt = read_file(os.path.join(test_ecs, 't', 'toy', f'toy-0.0{toolchain}.eb'))
+            toy_ec_txt = read_file(os.path.join(TEST_ECS_DIR, 't', 'toy', f'toy-0.0{toolchain}.eb'))
             toy_ec_txt += "\ntoolchainopts = {'rpath': False}\n"  # overwrites existing toolchainopts
             toy_ec = os.path.join(self.test_prefix, 'toy.eb')
             write_file(toy_ec, toy_ec_txt)
@@ -3049,8 +2977,7 @@ def grab_gcc_rpath_wrapper_args():
                 self._test_toy_build(ec_file=toy_ec, extra_args=['--rpath'], raise_error=True)
 
         # test check_readelf_rpath easyconfig parameter
-        test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec_txt = read_file(os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb'))
+        toy_ec_txt = TOY_EC_TXT
         toy_ec_txt += "\ncheck_readelf_rpath = False\n"
         toy_ec = os.path.join(self.test_prefix, 'toy.eb')
         write_file(toy_ec, toy_ec_txt)
@@ -3060,8 +2987,7 @@ def grab_gcc_rpath_wrapper_args():
     def test_toy_filter_rpath_sanity_libs(self):
         """Test use of --filter-rpath-sanity-libs."""
 
-        test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy-app', 'toy-app-0.0.eb')
+        toy_ec = os.path.join(TEST_ECS_DIR, 't', 'toy-app', 'toy-app-0.0.eb')
 
         # This should just build succesfully
         rpath_args = ['--rpath', '--strict-rpath-sanity-check']
@@ -3145,16 +3071,12 @@ def test_toy_filter_rpath_sanity_libs(self):
     def test_toy_cuda_sanity_check(self):
         """Test the CUDA sanity check"""
         update_build_option('trace', True)
-        # Define the toy_ec file we want to use
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        toy_ec = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-
         toy_bin = '%(installdir)s/bin/toy'
         py_site_pkgs = '%(installdir)s/lib/python3.9/site-packages'
         shlib_ext = get_shared_lib_ext()
 
         toy_ec_cuda = os.path.join(self.test_prefix, 'toy-0.0-cuda.eb')
-        toy_ec_txt = read_file(toy_ec)
+        toy_ec_txt = TOY_EC_TXT
         toy_ec_txt += '\n' + '\n'.join([
             "dependencies = [('CUDA', '5.5.22', '', SYSTEM)]",
             "postinstallcmds += [",
@@ -3316,7 +3238,7 @@ def assert_cuda_report(missing_cc, additional_cc, missing_ptx, log, stdout=None,
         # 8.0 device code
         # This should succeed (since the default for --cuda-sanity-check-error-on-failed-checks is False)
         # as to not break backwards compatibility
-        write_file(cuobjdump_file, cuobjdump_txt_shebang),
+        write_file(cuobjdump_file, cuobjdump_txt_shebang)
         write_file(cuobjdump_file, cuobjdump_txt_sm80, append=True)
         adjust_permissions(cuobjdump_file, stat.S_IXUSR, add=True)  # Make sure our mock cuobjdump is executable
         args = ['--cuda-compute-capabilities=8.0']
@@ -3434,7 +3356,7 @@ def assert_cuda_report(missing_cc, additional_cc, missing_ptx, log, stdout=None,
         # This is expected to succeed: the individual file which _would_ cause the sanity check to fail is
         # now on the ignore list
         toy_whitelist_ec = os.path.join(self.test_prefix, 'toy-0.0-cuda-whitelist.eb')
-        toy_ec_txt = read_file(toy_ec)
+        toy_ec_txt = TOY_EC_TXT
         toy_ec_txt += '\n' + '\n'.join([
             "dependencies = [('CUDA', '5.5.22', '', SYSTEM)]",
             "cuda_sanity_ignore_files = ['bin/toy']",
@@ -3458,7 +3380,7 @@ def assert_cuda_report(missing_cc, additional_cc, missing_ptx, log, stdout=None,
         # ordering (i.e. 9.0a > 9.0). It should pass, since device code is present for both CCs and PTX
         # code is present for the highest CC, and there is no additiona device code present
         # This also tests a case with multiple compute capabilities.
-        write_file(cuobjdump_file, cuobjdump_txt_shebang),
+        write_file(cuobjdump_file, cuobjdump_txt_shebang)
         write_file(cuobjdump_file, cuobjdump_txt_sm90, append=True)
         write_file(cuobjdump_file, cuobjdump_txt_sm90a, append=True)
         write_file(cuobjdump_file, cuobjdump_txt_sm90a_ptx, append=True)
@@ -3536,15 +3458,11 @@ def assert_cuda_report(missing_cc, additional_cc, missing_ptx, log, stdout=None,
 
     def test_toy_modaltsoftname(self):
         """Build two dependent toys as in test_toy_toy but using modaltsoftname"""
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        toy_ec_file = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec_file)
-
-        self.assertFalse(re.search('^modaltsoftname', toy_ec_txt, re.M))
+        self.assertFalse(re.search('^modaltsoftname', TOY_EC_TXT, re.M))
 
         ec1 = os.path.join(self.test_prefix, 'toy-0.0-one.eb')
         ec1_txt = '\n'.join([
-            toy_ec_txt,
+            TOY_EC_TXT,
             "versionsuffix = '-one'",
             "modaltsoftname = 'yot'"
         ])
@@ -3552,7 +3470,7 @@ def test_toy_modaltsoftname(self):
 
         ec2 = os.path.join(self.test_prefix, 'toy-0.0-two.eb')
         ec2_txt = '\n'.join([
-            toy_ec_txt,
+            TOY_EC_TXT,
             "versionsuffix = '-two'",
             "dependencies = [('toy', '0.0', '-one')]",
             "modaltsoftname = 'toytwo'",
@@ -3595,11 +3513,8 @@ def test_toy_modaltsoftname(self):
     def test_toy_build_trace(self):
         """Test use of --trace"""
 
-        topdir = os.path.dirname(os.path.abspath(__file__))
-        toy_ec_file = os.path.join(topdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
-        write_file(test_ec, read_file(toy_ec_file) + '\nsanity_check_commands = ["toy"]')
+        write_file(test_ec, TOY_EC_TXT + '\nsanity_check_commands = ["toy"]')
 
         self.mock_stderr(True)
         self.mock_stdout(True)
@@ -3641,9 +3556,8 @@ def test_toy_build_trace(self):
 
     def test_toy_build_hooks(self):
         """Test use of --hooks."""
-        toy_ec = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
         test_ec = os.path.join(self.test_prefix, 'test.eb')
-        test_ec_txt = read_file(toy_ec) + '\n'.join([
+        test_ec_txt = TOY_EC_TXT + '\n'.join([
             "exts_list = [('bar', '0.0'), ('toy', '0.0')]",
             "exts_defaultclass = 'DummyExtension'",
         ])
@@ -3802,9 +3716,7 @@ def post_build_and_install_loop_hook(ecs):
 
     def test_toy_multi_deps(self):
         """Test installation of toy easyconfig that uses multi_deps."""
-        test_ecs_dir = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs_dir, 't', 'toy', 'toy-0.0.eb')
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
 
         test_ec = os.path.join(self.test_prefix, 'test.eb')
 
@@ -4024,13 +3936,10 @@ def check_toy_load(depends_on=False):
 
     def test_fix_shebang(self):
         """Test use of fix_python_shebang_for & co."""
-        test_ecs_dir = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec_txt = read_file(os.path.join(test_ecs_dir, 't', 'toy', 'toy-0.0.eb'))
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
 
         test_ec_txt = '\n'.join([
-            toy_ec_txt,
+            TOY_EC_TXT,
             "postinstallcmds = ["
             # copy of bin/toy to use in fix_python_shebang_for and fix_perl_shebang_for
             "    'cp -a %(installdir)s/bin/toy %(installdir)s/bin/toy.python',",
@@ -4198,9 +4107,6 @@ def check_shebangs():
 
     def test_toy_system_toolchain_alias(self):
         """Test use of 'system' toolchain alias."""
-        toy_ec = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec)
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         tc_regex = re.compile('^toolchain = .*', re.M)
 
@@ -4211,7 +4117,7 @@ def test_toy_system_toolchain_alias(self):
         ]
 
         for tc in test_tcs:
-            test_ec_txt = tc_regex.sub(tc, toy_ec_txt)
+            test_ec_txt = tc_regex.sub(tc, TOY_EC_TXT)
             write_file(test_ec, test_ec_txt)
 
             with self.mocked_stdout_stderr():
@@ -4418,11 +4324,8 @@ def __exit__(self, type, value, traceback):
                 signal.alarm(0)
 
         # add extra sleep command to ensure session takes long enough
-        test_ecs_dir = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec_txt = read_file(os.path.join(test_ecs_dir, 't', 'toy', 'toy-0.0.eb'))
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
-        write_file(test_ec, toy_ec_txt + '\npostinstallcmds = ["sleep 10"]')
+        write_file(test_ec, TOY_EC_TXT + '\npostinstallcmds = ["sleep 10"]')
 
         extra_args = ['--locks-dir=%s' % locks_dir, '--wait-on-lock-limit=3', '--wait-on-lock-interval=3']
 
@@ -4460,16 +4363,12 @@ def test_toy_build_unicode_description(self):
         """Test installation of easyconfig file that has non-ASCII characters in description."""
         # cfr. https://github.com/easybuilders/easybuild-framework/issues/3284
 
-        test_ecs_dir = os.path.join(os.path.abspath(os.path.dirname(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs_dir, 't', 'toy', 'toy-0.0.eb')
-        toy_ec_txt = read_file(toy_ec)
-
         # the tilde character included here is a Unicode tilde character, not a regular ASCII tilde (~)
         descr = "This description includes a unicode tilde character: ∼, for your entertainment."
         self.assertNotIn('~', descr)
 
         regex = re.compile(r'^description\s*=.*', re.M)
-        test_ec_txt = regex.sub(r'description = "%s"' % descr, toy_ec_txt)
+        test_ec_txt = regex.sub(r'description = "%s"' % descr, TOY_EC_TXT)
 
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         write_file(test_ec, test_ec_txt)
@@ -4517,13 +4416,8 @@ def test_toy_build_lib64_lib_symlink(self):
     def test_toy_build_lib_lib64_symlink(self):
         """Check whether lib64 symlink to lib subdirectory is created."""
 
-        test_ecs = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-
-        test_ec_txt = read_file(toy_ec)
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
-        write_file(test_ec, test_ec_txt)
+        write_file(test_ec, TOY_EC_TXT)
 
         # by default, lib -> lib64 symlink is created (--lib-lib64-symlink is enabled by default)
         with self.mocked_stdout_stderr():
@@ -4561,8 +4455,7 @@ def test_toy_build_lib_lib64_symlink(self):
     def test_toy_build_sanity_check_linked_libs(self):
         """Test sanity checks for banned/requires libraries."""
 
-        test_ecs = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs')
-        libtoy_ec = os.path.join(test_ecs, 'l', 'libtoy', 'libtoy-0.0.eb')
+        libtoy_ec = os.path.join(TEST_ECS_DIR, 'l', 'libtoy', 'libtoy-0.0.eb')
 
         libtoy_modfile_path = os.path.join(self.test_installpath, 'modules', 'all', 'libtoy', '0.0')
         if get_module_syntax() == 'Lua':
@@ -4650,9 +4543,7 @@ def test_toy_build_sanity_check_linked_libs(self):
 
     def test_toy_mod_files(self):
         """Check detection of .mod files"""
-        test_ecs = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         write_file(test_ec, test_ec_txt)
 
@@ -4698,10 +4589,7 @@ def test_toy_post_install_patches(self):
         """
         Test use of post-install patches
         """
-        test_ecs = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += "\npostinstallpatches = ['toy-0.0_fix-README.patch']"
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         write_file(test_ec, test_ec_txt)
@@ -4720,10 +4608,7 @@ def test_toy_unavailable_os_dep(self):
         Existence of OS dependencies is checking during the parsing of the easyconfig.
         Test here that this problem is caught and a test report generated (#4102).
         """
-        test_ecs = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += "\nosdependencies = [('package-does-not-exist')]"
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         write_file(test_ec, test_ec_txt)
@@ -4751,10 +4636,7 @@ def test_toy_post_install_messages(self):
         """
         Test use of post-install messages
         """
-        test_ecs = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += "\npostinstallmsgs = ['This is post install message 1', 'This is post install message 2']"
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         write_file(test_ec, test_ec_txt)
@@ -4780,10 +4662,7 @@ def test_toy_build_info_msg(self):
         """
         Test use of build info message
         """
-        test_ecs = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += '\nbuild_info_msg = "Are you sure you want to install this toy software?"'
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         write_file(test_ec, test_ec_txt)
@@ -4804,13 +4683,11 @@ def test_toy_failing_test_step(self):
         """
         Test behaviour when test step fails, using toy easyconfig.
         """
-        test_ecs = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
         toy_mod_path = os.path.join(self.test_installpath, 'modules', 'all', 'toy', '0.0')
         if get_module_syntax() == 'Lua':
             toy_mod_path += '.lua'
 
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += '\nruntest = "false"'
         test_ec = os.path.join(self.test_prefix, 'test.eb')
         write_file(test_ec, test_ec_txt)
@@ -4827,7 +4704,7 @@ def test_toy_failing_test_step(self):
         remove_file(toy_mod_path)
 
         # ignoring test failure should also work if an EasyBuildError is raises from test step
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += '\nruntest = "RAISE_ERROR"'
         write_file(test_ec, test_ec_txt)
 
@@ -4840,6 +4717,25 @@ def test_toy_failing_test_step(self):
                                             raise_error=True, verbose=True)
         self.assertExists(toy_mod_path)
 
+    def test_system_ec_with_gcccore_build_dep(self):
+        """
+        Test building a SYSTEM level software that has a module from GCCcore as build dependency"""
+        test_ec_txt = TOY_EC_TXT
+        # Using a software with existing (test) module and no dependencies itself for simplicity
+        test_ec_txt += "\nbuilddependencies = [('ncurses', '6.4', '', ('GCCcore', '12.3.0'))]"
+        test_ec = os.path.join(self.test_prefix, 'test.eb')
+        write_file(test_ec, test_ec_txt)
+        common_args = ["--rebuild", test_ec]
+        for mns in ['EasyBuildMNS', 'HierarchicalMNS']:
+            with self.subTest(mns=mns):
+                args = common_args + [f'--module-naming-scheme={mns}']
+                modulepath = os.path.join(TEST_DIR, 'modules')
+                if mns == 'HierarchicalMNS':
+                    modulepath = os.path.join(modulepath, 'HierarchicalMNS')
+                os.environ['MODULEPATH'] = modulepath
+                outtxt = self.run_eb_main_capture_output(args, do_build=True, verbose=True, raise_error=True)
+                self.assertRegex(outtxt, r'\[SUCCESS\] .*toy/0.0')
+
     def test_eb_crash(self):
         """
         Test behaviour when EasyBuild crashes, for example due to a buggy hook
@@ -4851,12 +4747,10 @@ def pre_configure_hook(self, *args, **kwargs):
         """)
         write_file(hooks_file, hooks_file_txt)
 
-        topdir = os.path.dirname(os.path.dirname(os.path.dirname(__file__)))
-        toy_eb = os.path.join(topdir, 'test', 'framework', 'sandbox', 'easybuild', 'easyblocks', 't', 'toy.py')
-        toy_ec = os.path.join(topdir, 'test', 'framework', 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
+        toy_eb = os.path.join(TEST_DIR, 'sandbox', 'easybuild', 'easyblocks', 't', 'toy.py')
 
         args = [
-            toy_ec,
+            TOY_EC,
             f'--hooks={hooks_file}',
             '--force',
             f'--installpath={self.test_prefix}',
@@ -4867,7 +4761,7 @@ def pre_configure_hook(self, *args, **kwargs):
             cleanup()
             try:
                 main_with_hooks(args=args)
-                self.assertFalse("This should never be reached, main function should have crashed!")
+                self.fail("This should never be reached, main function should have crashed!")
             except NameError as err:
                 self.assertEqual(str(err), "name 'no_such_thing' is not defined")
 
@@ -4879,11 +4773,8 @@ def test_eb_error(self):
         """
         Test whether main function as run by 'eb' command print error messages to stderr.
         """
-        topdir = os.path.dirname(os.path.dirname(os.path.dirname(__file__)))
-        toy_ec = os.path.join(topdir, 'test', 'framework', 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb')
-
         test_ec = os.path.join(self.test_prefix, 'test.eb')
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += "\ndependencies = [('nosuchdep', '1.0')]"
         write_file(test_ec, test_ec_txt)
 
@@ -4914,10 +4805,7 @@ def test_toy_python(self):
                 write_file(fake_python_mod, '#%Module')
         self.modtool.use(fake_mods_path)
 
-        test_ecs = os.path.join(os.path.dirname(__file__), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-
-        test_ec_txt = read_file(toy_ec)
+        test_ec_txt = TOY_EC_TXT
         test_ec_txt += "\npostinstallcmds.append('mkdir -p %(installdir)s/lib/python3.6/site-packages')"
         test_ec_txt += "\npostinstallcmds.append('touch %(installdir)s/lib/python3.6/site-packages/foo.py')"
 
@@ -4966,13 +4854,10 @@ def test_toy_multiple_ecs_module(self):
         """
         Verify whether module file is correct when multiple easyconfigs are being installed.
         """
-        test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
-        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
-
         # modify 'toy' easyconfig so toy-headers subdirectory is created,
         # which is taken into account by EB_toy easyblock for $CPATH
         test_toy_ec = os.path.join(self.test_prefix, 'test-toy.eb')
-        toy_ec_txt = read_file(toy_ec)
+        toy_ec_txt = TOY_EC_TXT
         toy_ec_txt += "\npostinstallcmds += ['mkdir %(installdir)s/toy-headers']"
         toy_ec_txt += "\npostinstallcmds += ['touch %(installdir)s/toy-headers/toy.h']"
         write_file(test_toy_ec, toy_ec_txt)
@@ -4980,7 +4865,7 @@ def test_toy_multiple_ecs_module(self):
         # modify 'toy-app' easyconfig so toy-headers subdirectory is created,
         # which is consider by EB_toy easyblock for $CPATH,
         # but should *not* be actually used because software name is not 'toy'
-        toy_app_ec = os.path.join(test_ecs, 't', 'toy-app', 'toy-app-0.0.eb')
+        toy_app_ec = os.path.join(TEST_ECS_DIR, 't', 'toy-app', 'toy-app-0.0.eb')
         test_toy_app_ec = os.path.join(self.test_prefix, 'test-toy-app.eb')
         toy_ec_txt = read_file(toy_app_ec)
         toy_ec_txt += "\npostinstallcmds += ['mkdir %(installdir)s/toy-headers']"