diff --git a/.vscode/launch.template.json b/.vscode/launch.template.json
index 81fe0ec776..769898213b 100644
--- a/.vscode/launch.template.json
+++ b/.vscode/launch.template.json
@@ -17,6 +17,17 @@
             ],
             "autoAttachChildProcesses": true,
             "preLaunchTask": "Watch for extension run"
+        },
+        {
+            "name": "Launch submodule test",
+            "type": "go",
+            "request": "launch",
+            "mode": "test",
+            "program": "${workspaceFolder}/internal/testrunner",
+            "args": [
+                "-test.run",
+                "TestSubmodule/${fileBasename}"
+            ]
         }
     ]
 }
diff --git a/internal/testutil/runner/compiler_runner.go b/internal/testrunner/compiler_runner.go
similarity index 100%
rename from internal/testutil/runner/compiler_runner.go
rename to internal/testrunner/compiler_runner.go
diff --git a/internal/testrunner/compiler_runner_test.go b/internal/testrunner/compiler_runner_test.go
new file mode 100644
index 0000000000..910e00b942
--- /dev/null
+++ b/internal/testrunner/compiler_runner_test.go
@@ -0,0 +1,50 @@
+package runner
+
+import (
+	"testing"
+
+	"github.com/microsoft/typescript-go/internal/bundled"
+	"github.com/microsoft/typescript-go/internal/core"
+	"github.com/microsoft/typescript-go/internal/repo"
+	"github.com/microsoft/typescript-go/internal/tspath"
+	"gotest.tools/v3/assert"
+)
+
+// Runs the new compiler tests and produces baselines (e.g. `test1.symbols`).
+func TestLocal(t *testing.T) { runCompilerTests(t, false) } //nolint:paralleltest
+
+// Runs the old compiler tests, and produces new baselines (e.g. `test1.symbols`)
+// and a diff between the new and old baselines (e.g. `test1.symbols.diff`).
+func TestSubmodule(t *testing.T) { runCompilerTests(t, true) } //nolint:paralleltest
+
+func runCompilerTests(t *testing.T, isSubmodule bool) {
+	t.Parallel()
+
+	if isSubmodule {
+		repo.SkipIfNoTypeScriptSubmodule(t)
+	}
+
+	if !bundled.Embedded {
+		// Without embedding, we'd need to read all of the lib files out from disk into the MapFS.
+		// Just skip this for now.
+		t.Skip("bundled files are not embedded")
+	}
+
+	runners := []*CompilerBaselineRunner{
+		NewCompilerBaselineRunner(TestTypeRegression, isSubmodule),
+		NewCompilerBaselineRunner(TestTypeConformance, isSubmodule),
+	}
+
+	var seenTests core.Set[string]
+	for _, runner := range runners {
+		for _, test := range runner.EnumerateTestFiles() {
+			test = tspath.GetBaseFileName(test)
+			assert.Assert(t, !seenTests.Has(test), "Duplicate test file: %s", test)
+			seenTests.Add(test)
+		}
+	}
+
+	for _, runner := range runners {
+		runner.RunTests(t)
+	}
+}
diff --git a/internal/testutil/runner/runner.go b/internal/testrunner/runner.go
similarity index 100%
rename from internal/testutil/runner/runner.go
rename to internal/testrunner/runner.go
diff --git a/internal/testutil/runner/test_case_parser.go b/internal/testrunner/test_case_parser.go
similarity index 100%
rename from internal/testutil/runner/test_case_parser.go
rename to internal/testrunner/test_case_parser.go
diff --git a/internal/testutil/runner/test_case_parser_test.go b/internal/testrunner/test_case_parser_test.go
similarity index 100%
rename from internal/testutil/runner/test_case_parser_test.go
rename to internal/testrunner/test_case_parser_test.go
diff --git a/internal/testutil/runner/compiler_runner_test.go b/internal/testutil/runner/compiler_runner_test.go
deleted file mode 100644
index 6f212417d4..0000000000
--- a/internal/testutil/runner/compiler_runner_test.go
+++ /dev/null
@@ -1,50 +0,0 @@
-package runner
-
-import (
-	"testing"
-
-	"github.com/microsoft/typescript-go/internal/bundled"
-	"github.com/microsoft/typescript-go/internal/repo"
-)
-
-// Runs the new compiler tests and produces baselines (e.g. `test1.symbols`).
-func TestCompilerBaselinesLocal(t *testing.T) {
-	t.Parallel()
-
-	if !bundled.Embedded {
-		// Without embedding, we'd need to read all of the lib files out from disk into the MapFS.
-		// Just skip this for now.
-		t.Skip("bundled files are not embedded")
-	}
-
-	testTypes := []CompilerTestType{TestTypeRegression, TestTypeConformance}
-	for _, testType := range testTypes {
-		t.Run(testType.String(), func(t *testing.T) {
-			t.Parallel()
-			runner := NewCompilerBaselineRunner(testType, false /*isSubmodule*/)
-			runner.RunTests(t)
-		})
-	}
-}
-
-// Runs the old compiler tests, and produces new baselines (e.g. `test1.symbols`)
-// and a diff between the new and old baselines (e.g. `test1.symbols.diff`).
-func TestCompilerBaselinesSubmodule(t *testing.T) {
-	t.Parallel()
-	repo.SkipIfNoTypeScriptSubmodule(t)
-
-	if !bundled.Embedded {
-		// Without embedding, we'd need to read all of the lib files out from disk into the MapFS.
-		// Just skip this for now.
-		t.Skip("bundled files are not embedded")
-	}
-
-	testTypes := []CompilerTestType{TestTypeRegression, TestTypeConformance}
-	for _, testType := range testTypes {
-		t.Run(testType.String(), func(t *testing.T) {
-			t.Parallel()
-			runner := NewCompilerBaselineRunner(testType, true /*isSubmodule*/)
-			runner.RunTests(t)
-		})
-	}
-}