diff --git a/go/packages/packagestest/export.go b/go/packages/packagestest/export.go
index ad38ebf1..14424951 100644
--- a/go/packages/packagestest/export.go
+++ b/go/packages/packagestest/export.go
@@ -136,6 +136,7 @@ func Export(t testing.TB, exporter Exporter, modules []Module) *Exported {
 			Dir:     temp,
 			Env:     append(os.Environ(), "GOPACKAGESDRIVER=off"),
 			Overlay: make(map[string][]byte),
+			Tests:   true,
 		},
 		Modules: modules,
 		temp:    temp,
diff --git a/internal/lsp/lsp_test.go b/internal/lsp/lsp_test.go
index 73d614e3..94bad72a 100644
--- a/internal/lsp/lsp_test.go
+++ b/internal/lsp/lsp_test.go
@@ -36,7 +36,7 @@ func testLSP(t *testing.T, exporter packagestest.Exporter) {
 	// We hardcode the expected number of test cases to ensure that all tests
 	// are being executed. If a test is added, this number must be changed.
 	const expectedCompletionsCount = 63
-	const expectedDiagnosticsCount = 13
+	const expectedDiagnosticsCount = 14
 	const expectedFormatCount = 3
 	const expectedDefinitionsCount = 16
 	const expectedTypeDefinitionsCount = 2
diff --git a/internal/lsp/testdata/testy/testy.go b/internal/lsp/testdata/testy/testy.go
new file mode 100644
index 00000000..a72cef89
--- /dev/null
+++ b/internal/lsp/testdata/testy/testy.go
@@ -0,0 +1,3 @@
+package testy
+
+func a() {}
diff --git a/internal/lsp/testdata/testy/testy_test.go b/internal/lsp/testdata/testy/testy_test.go
new file mode 100644
index 00000000..b1e0c82d
--- /dev/null
+++ b/internal/lsp/testdata/testy/testy_test.go
@@ -0,0 +1,8 @@
+package testy
+
+import "testing"
+
+func TestSomething(t *testing.T) { //@item(TestSomething, "TestSomething(t *testing.T)", "", "func")
+	var x int //@diag("x", "x declared but not used")
+	a()
+}