fix(cli): scope test discovery to package

compiler/main.go

@@ -1112,15 +1112,24 @@ func discoverTestFiles(inputPath string) ([]string, error) {
 		return []string{filepath.Clean(inputPath)}, nil
 	}
 
+	inputPath = filepath.Clean(inputPath)
 	files := make([]string, 0)
 	seen := make(map[string]struct{})
 	err = filepath.WalkDir(inputPath, func(path string, entry os.DirEntry, walkErr error) error {
 		if walkErr != nil {
 			return walkErr
 		}
 		if entry.IsDir() {
-			if strings.HasPrefix(entry.Name(), ".") && path != inputPath {
+			if path == inputPath {
+				return nil
+			}
+			if strings.HasPrefix(entry.Name(), ".") {
+				return filepath.SkipDir
+			}
+			if _, manifestErr := os.Stat(filepath.Join(path, "ard.toml")); manifestErr == nil {
 				return filepath.SkipDir
+			} else if !os.IsNotExist(manifestErr) {
+				return manifestErr
 			}
 			return nil
 		}

compiler/main_test.go

@@ -825,6 +825,39 @@ test fn panics() Void!Str {
 		}
 	})
 }
+func TestDiscoverTestFilesSkipsNestedProjects(t *testing.T) {
+	projectDir := t.TempDir()
+	if err := os.WriteFile(filepath.Join(projectDir, "ard.toml"), []byte("name = \"root\"\nard = \">= 0.1.0\"\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	rootTest := filepath.Join(projectDir, "test", "root_test.ard")
+	if err := os.MkdirAll(filepath.Dir(rootTest), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(rootTest, []byte("test fn root_test() {}\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	nestedDir := filepath.Join(projectDir, "examples", "hello")
+	if err := os.MkdirAll(nestedDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(nestedDir, "ard.toml"), []byte("name = \"hello\"\nard = \">= 0.1.0\"\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(nestedDir, "main.ard"), []byte("fn main() {}\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	files, err := discoverTestFiles(projectDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(files) != 1 || files[0] != rootTest {
+		t.Fatalf("discovered files = %v, want [%s]", files, rootTest)
+	}
+}
+
 func TestTestCommandDisambiguatesSameNamedTestsInSingleRun(t *testing.T) {
 	dir := t.TempDir()
 	projectDir := filepath.Join(dir, "project")