Fix t/op/chdir.t - All 51 tests passing (100%)

Three fixes to get chdir.t working:

1. Exporter.java: Add support for :DEFAULT export tag
   - :DEFAULT now correctly expands to @export contents
   - Fixes File::Spec::Functions import issue

2. perl_test_runner.pl: Fix working directory for t/ tests
   - Tests in t/op/, t/base/, etc. now run from t/ directory
   - Allows tests to require './test.pl' correctly

3. Directory.java: Complete chdir() implementation
   - chdir('') now fails with ENOENT (errno 2)
   - chdir() checks HOME, LOGDIR, SYS$LOGIN env vars
   - SYS$LOGIN only checked on VMS, not darwin/macOS
   - Proper errno values: ENOENT (2) and EINVAL (22)
   - fchdir throws 'unimplemented' error for filehandles

Test Results:
- Before: 0/0 tests (compilation error)
- After: 51/51 tests passing (100%)

Author: fglock

dev/tools/perl_test_runner.pl

@@ -278,6 +278,11 @@ sub run_single_test {
             $local_test_dir =~ s{/[^/]+$}{};
         }
     }
+    # For tests in t/ directory (t/op/, t/base/, etc.), change to t/
+    # so they can find ./test.pl via require
+    elsif ($test_file =~ m{^t/}) {
+        $local_test_dir = 't';
+    }
 
     chdir($local_test_dir) if $local_test_dir && -d $local_test_dir;
 

src/main/java/org/perlonjava/operators/Directory.java

@@ -36,14 +36,66 @@ public static RuntimeScalar chdir(RuntimeScalar runtimeScalar) {
         //            directory handle as the argument. On systems that don't support
         //            fchdir(2), passing handles raises an exception.
 
-        String dirName = runtimeScalar.toString();
+        String dirName;
+        
+        // Check if argument is a filehandle or dirhandle
+        if (runtimeScalar.value instanceof RuntimeIO || runtimeScalar.value instanceof RuntimeGlob) {
+            // Try to get RuntimeIO from the scalar
+            RuntimeIO io = RuntimeIO.getRuntimeIO(runtimeScalar);
+            if (io != null) {
+                // This is a filehandle or dirhandle - fchdir is not supported
+                throw new PerlCompilerException("The fchdir function is unimplemented");
+            }
+        }
+        
+        // Handle chdir() with no arguments - check environment variables
+        if (!runtimeScalar.defined().getBoolean()) {
+            // Try HOME, then LOGDIR, then SYS$LOGIN (for VMS only)
+            RuntimeHash envHash = GlobalVariable.getGlobalHash("main::ENV");
+            RuntimeScalar homeDir = envHash.get("HOME");
+            if (homeDir != null && homeDir.defined().getBoolean() && !homeDir.toString().isEmpty()) {
+                dirName = homeDir.toString();
+            } else {
+                RuntimeScalar logDir = envHash.get("LOGDIR");
+                if (logDir != null && logDir.defined().getBoolean() && !logDir.toString().isEmpty()) {
+                    dirName = logDir.toString();
+                } else {
+                    // Check SYS$LOGIN only on VMS
+                    String osName = GlobalVariable.getGlobalVariable("main::^O").toString();
+                    if ("VMS".equalsIgnoreCase(osName)) {
+                        RuntimeScalar sysLogin = envHash.get("SYS$LOGIN");
+                        if (sysLogin != null && sysLogin.defined().getBoolean() && !sysLogin.toString().isEmpty()) {
+                            dirName = sysLogin.toString();
+                        } else {
+                            // No environment variable set - fail with EINVAL
+                            getGlobalVariable("main::!").set(22);  // EINVAL
+                            return scalarFalse;
+                        }
+                    } else {
+                        // Not VMS and no HOME/LOGDIR - fail with EINVAL
+                        getGlobalVariable("main::!").set(22);  // EINVAL
+                        return scalarFalse;
+                    }
+                }
+            }
+        } else {
+            dirName = runtimeScalar.toString();
+        }
+        
+        // Check for empty string - should fail with ENOENT
+        if (dirName.isEmpty()) {
+            getGlobalVariable("main::!").set(2);  // ENOENT
+            return scalarFalse;
+        }
+        
         File absoluteDir = RuntimeIO.resolveFile(dirName);
 
         if (absoluteDir.exists() && absoluteDir.isDirectory()) {
             System.setProperty("user.dir", absoluteDir.getAbsolutePath());
             return scalarTrue;
         } else {
-            getGlobalVariable("main::!").set("chdir failed: No such directory '" + dirName + "'");
+            // Set errno to ENOENT (No such file or directory)
+            getGlobalVariable("main::!").set(2);  // ENOENT
             return scalarFalse;
         }
     }

src/main/java/org/perlonjava/perlmodule/Exporter.java

@@ -174,13 +174,21 @@ public static RuntimeList exportToLevel(RuntimeArray args, int ctx) {
 
             if (symbolString.startsWith(":")) {
                 String tagName = symbolString.substring(1);
-                RuntimeScalar tagValue = exportTags.get(tagName);
-                if (tagValue == null || tagValue.type != RuntimeScalarType.ARRAYREFERENCE) {
-                    throw new PerlCompilerException("Invalid or unknown export tag: " + tagName);
-                }
-                RuntimeArray tagSymbols = tagValue.arrayDeref();
-                if (tagSymbols != null) {
-                    tagArray.elements.addAll(tagSymbols.elements);
+                
+                // Handle special :DEFAULT tag - it means "use @EXPORT"
+                if ("DEFAULT".equals(tagName)) {
+                    if (export != null && !export.elements.isEmpty()) {
+                        tagArray.elements.addAll(export.elements);
+                    }
+                } else {
+                    RuntimeScalar tagValue = exportTags.get(tagName);
+                    if (tagValue == null || tagValue.type != RuntimeScalarType.ARRAYREFERENCE) {
+                        throw new PerlCompilerException("Invalid or unknown export tag: " + tagName);
+                    }
+                    RuntimeArray tagSymbols = tagValue.arrayDeref();
+                    if (tagSymbols != null) {
+                        tagArray.elements.addAll(tagSymbols.elements);
+                    }
                 }
             } else {
                 tagArray.elements.add(symbolObj);