diff --git a/crates/konvoy-config/src/lockfile.rs b/crates/konvoy-config/src/lockfile.rs
index 786725c..de1e3ad 100644
--- a/crates/konvoy-config/src/lockfile.rs
+++ b/crates/konvoy-config/src/lockfile.rs
@@ -1167,4 +1167,35 @@ url = "https://example.com/plugin.jar"
             }
         }
     }
+
+    #[test]
+    fn has_maven_entry_finds_maven_dep() {
+        let mut lockfile = Lockfile::default();
+        lockfile.dependencies.push(DependencyLock {
+            name: "kotlinx-coroutines".to_owned(),
+            source: DepSource::Maven {
+                version: "1.8.0".to_owned(),
+                maven: "org.jetbrains.kotlinx:kotlinx-coroutines-core".to_owned(),
+                targets: std::collections::BTreeMap::new(),
+                required_by: Vec::new(),
+                classifier: None,
+            },
+            source_hash: "abc".to_owned(),
+        });
+        assert!(lockfile.has_maven_entry("kotlinx-coroutines"));
+        assert!(!lockfile.has_maven_entry("nonexistent"));
+    }
+
+    #[test]
+    fn has_maven_entry_ignores_path_deps() {
+        let mut lockfile = Lockfile::default();
+        lockfile.dependencies.push(DependencyLock {
+            name: "my-lib".to_owned(),
+            source: DepSource::Path {
+                path: "../my-lib".to_owned(),
+            },
+            source_hash: "abc".to_owned(),
+        });
+        assert!(!lockfile.has_maven_entry("my-lib"));
+    }
 }
diff --git a/crates/konvoy-config/src/manifest.rs b/crates/konvoy-config/src/manifest.rs
index ef55470..6ea0e5c 100644
--- a/crates/konvoy-config/src/manifest.rs
+++ b/crates/konvoy-config/src/manifest.rs
@@ -1667,4 +1667,44 @@ version = "1.0"
             }
         }
     }
+
+    #[test]
+    fn is_maven_true_when_both_set() {
+        let spec = DependencySpec {
+            path: None,
+            maven: Some("org.example:lib".to_owned()),
+            version: Some("1.0.0".to_owned()),
+        };
+        assert!(spec.is_maven());
+    }
+
+    #[test]
+    fn is_maven_false_when_maven_only() {
+        let spec = DependencySpec {
+            path: None,
+            maven: Some("org.example:lib".to_owned()),
+            version: None,
+        };
+        assert!(!spec.is_maven());
+    }
+
+    #[test]
+    fn is_maven_false_when_version_only() {
+        let spec = DependencySpec {
+            path: None,
+            maven: None,
+            version: Some("1.0.0".to_owned()),
+        };
+        assert!(!spec.is_maven());
+    }
+
+    #[test]
+    fn is_maven_false_for_path_dep() {
+        let spec = DependencySpec {
+            path: Some("../lib".to_owned()),
+            maven: None,
+            version: None,
+        };
+        assert!(!spec.is_maven());
+    }
 }
diff --git a/crates/konvoy-engine/src/error.rs b/crates/konvoy-engine/src/error.rs
index 833e0be..e76caff 100644
--- a/crates/konvoy-engine/src/error.rs
+++ b/crates/konvoy-engine/src/error.rs
@@ -201,3 +201,24 @@ pub(crate) fn map_artifact_download_err(
         other => EngineError::Util(other),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn map_artifact_download_err_passes_through_other_errors() {
+        let err = konvoy_util::error::UtilError::NoHomeDir;
+        let result = map_artifact_download_err(
+            "test",
+            err,
+            |_, _| panic!("download_err should not be called"),
+            |_, _, _| panic!("hash_err should not be called"),
+        );
+        let msg = result.to_string();
+        assert!(
+            msg.contains("home directory"),
+            "other errors should pass through: {msg}"
+        );
+    }
+}
diff --git a/crates/konvoy-engine/src/plugin.rs b/crates/konvoy-engine/src/plugin.rs
index 46e5633..af8f5ac 100644
--- a/crates/konvoy-engine/src/plugin.rs
+++ b/crates/konvoy-engine/src/plugin.rs
@@ -771,4 +771,24 @@ mod tests {
             plugins,
         }
     }
+
+    #[test]
+    fn ensure_plugin_artifacts_locked_mode_requires_hash() {
+        // In --locked mode, a plugin without a lockfile hash should fail.
+        let manifest = make_manifest_with_plugin(
+            "kotlin-serialization",
+            "org.jetbrains.kotlin:kotlin-serialization-compiler-plugin",
+            "2.1.0",
+        );
+        let artifacts = resolve_plugin_artifacts(&manifest).unwrap();
+        let lockfile = Lockfile::default(); // no plugin hashes
+
+        let result = ensure_plugin_artifacts(&artifacts, &lockfile, true);
+        assert!(
+            result.is_err(),
+            "expected error in locked mode without hash"
+        );
+        let err = result.unwrap_err().to_string();
+        assert!(err.contains("lockfile is out of date"), "error was: {err}");
+    }
 }
diff --git a/crates/konvoy-targets/src/lib.rs b/crates/konvoy-targets/src/lib.rs
index bca6c30..4137218 100644
--- a/crates/konvoy-targets/src/lib.rs
+++ b/crates/konvoy-targets/src/lib.rs
@@ -333,4 +333,42 @@ mod tests {
             }
         }
     }
+
+    #[test]
+    fn is_host_returns_true_for_host_target() {
+        // host_target() succeeds on all supported CI platforms.
+        if let Ok(host) = host_target() {
+            assert!(
+                host.is_host().unwrap_or(false),
+                "host target should match itself"
+            );
+        }
+    }
+
+    #[test]
+    fn is_host_returns_false_for_other_target() {
+        // Pick a target that's not the current host.
+        let host = match host_target() {
+            Ok(h) => h,
+            Err(_) => return, // skip on unsupported platforms
+        };
+        let other_name = if host.to_konanc_arg() == "linux_x64" {
+            "macos_arm64"
+        } else {
+            "linux_x64"
+        };
+        let other: Target = other_name.parse().unwrap();
+        assert!(
+            !other.is_host().unwrap_or(true),
+            "non-host target should not match host"
+        );
+    }
+
+    #[test]
+    fn display_matches_konanc_arg() {
+        for &name in KNOWN_TARGETS {
+            let target: Target = name.parse().unwrap();
+            assert_eq!(target.to_string(), target.to_konanc_arg());
+        }
+    }
 }
diff --git a/crates/konvoy-util/src/maven.rs b/crates/konvoy-util/src/maven.rs
index 5c71e55..52fc5c7 100644
--- a/crates/konvoy-util/src/maven.rs
+++ b/crates/konvoy-util/src/maven.rs
@@ -385,4 +385,65 @@ mod tests {
             "new() should default classifier to None"
         );
     }
+
+    #[test]
+    fn parse_rejects_empty_group_id() {
+        let result = MavenCoordinate::parse(":artifact:1.0.0");
+        assert!(result.is_err());
+        let err = result.unwrap_err().to_string();
+        assert!(err.contains("group_id is empty"), "error was: {err}");
+    }
+
+    #[test]
+    fn parse_rejects_empty_artifact_id() {
+        let result = MavenCoordinate::parse("group::1.0.0");
+        assert!(result.is_err());
+        let err = result.unwrap_err().to_string();
+        assert!(err.contains("artifact_id is empty"), "error was: {err}");
+    }
+
+    #[test]
+    fn parse_rejects_empty_version() {
+        let result = MavenCoordinate::parse("group:artifact:");
+        assert!(result.is_err());
+        let err = result.unwrap_err().to_string();
+        assert!(err.contains("version is empty"), "error was: {err}");
+    }
+
+    #[test]
+    fn parse_rejects_empty_packaging() {
+        let result = MavenCoordinate::parse("group:artifact:1.0.0:");
+        assert!(result.is_err());
+        let err = result.unwrap_err().to_string();
+        assert!(err.contains("packaging is empty"), "error was: {err}");
+    }
+
+    #[test]
+    fn maven_artifact_url_format() {
+        let url = super::maven_artifact_url(
+            "org.jetbrains.kotlinx",
+            "kotlinx-coroutines-core",
+            "1.8.0",
+            "pom",
+        );
+        assert_eq!(
+            url,
+            "https://repo1.maven.org/maven2/org/jetbrains/kotlinx/kotlinx-coroutines-core/1.8.0/kotlinx-coroutines-core-1.8.0.pom"
+        );
+    }
+
+    #[test]
+    fn maven_artifact_url_module_extension() {
+        let url = super::maven_artifact_url("org.example", "lib", "2.0.0", "module");
+        assert!(url.ends_with("lib-2.0.0.module"), "url was: {url}");
+    }
+
+    #[test]
+    fn cache_path_matches_repository_path() {
+        let coord = MavenCoordinate::new("org.example", "lib", "1.0.0");
+        let cache_root = Path::new("/cache");
+        let cache_path = coord.cache_path(cache_root);
+        let expected = cache_root.join(coord.repository_path());
+        assert_eq!(cache_path, expected);
+    }
 }