ci: run tests under the race detector

integration/integration_azurerm_test.go

@@ -244,8 +244,7 @@ func TestAPIDiscoveryAzureRM(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			scenario(t, "api/azurerm", tt.name)
-			gh := newMockGitHub(t, "testdata/azurerm", azurermPRs)
-			gh.conflicted = conflictedPRs
+			gh := newMockGitHub(t, "testdata/azurerm", azurermPRs, withConflicted(conflictedPRs))
 			tc := newMockTeamCity(t)
 
 			res := runTCTest(t, azurermEnv(gh, tc), tt.args...)
@@ -381,8 +380,7 @@ func TestASTDiscoveryAzureRM(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			scenario(t, "ast/azurerm", tt.name)
-			gh := newMockGitHub(t, "testdata/azurerm", azurermASTPRs)
-			gh.conflicted = conflictedPRs
+			gh := newMockGitHub(t, "testdata/azurerm", azurermASTPRs, withConflicted(conflictedPRs))
 			tc := newMockTeamCity(t)
 			env := azurermEnv(gh, tc)
 			env["TCTEST_LOCAL_REPO_PATH"] = cloneUpstream(t, azurermUpstream)
@@ -426,8 +424,7 @@ func TestErrorMessages(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			scenario(t, "errors/azurerm", tt.name)
-			gh := newMockGitHub(t, "testdata/azurerm", azurermPRs)
-			gh.conflicted = conflictedPRs
+			gh := newMockGitHub(t, "testdata/azurerm", azurermPRs, withConflicted(conflictedPRs))
 			tc := newMockTeamCity(t)
 
 			res := runTCTest(t, azurermEnv(gh, tc), tt.args...)
@@ -529,8 +526,7 @@ func TestPrsCommand(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			scenario(t, "prs/azurerm", tt.name)
-			gh := newMockGitHub(t, "testdata/azurerm", azurermPRs)
-			gh.openPRs = openPRs
+			gh := newMockGitHub(t, "testdata/azurerm", azurermPRs, withOpenPRs(openPRs))
 			tc := newMockTeamCity(t)
 
 			res := runTCTest(t, azurermEnv(gh, tc), tt.args...)

integration/integration_test.go

@@ -52,10 +52,11 @@ func TestMain(m *testing.M) {
 			return 1
 		}
 
-		// build the real binary once
+		// build the real binary once, race-instrumented so a data race in the CLI surfaces as a test failure (the
+		// race runtime prints a report and exits non-zero, which the exit-code and output assertions catch)
 		binPath = filepath.Join(tmp, "tctest")
-		build := exec.CommandContext(context.Background(), "go", "build", "-o", binPath, ".") //nolint:gosec // building the repo's own binary into a temp dir
-		build.Dir = ".."                                                                      // tests run with CWD = the test package dir
+		build := exec.CommandContext(context.Background(), "go", "build", "-race", "-o", binPath, ".") //nolint:gosec // building the repo's own binary into a temp dir
+		build.Dir = ".."                                                                               // tests run with CWD = the test package dir
 		if out, err := build.CombinedOutput(); err != nil {
 			fmt.Fprintf(os.Stderr, "integration test setup: building tctest: %v\n%s\n", err, out)
 			return 1
@@ -186,12 +187,31 @@ type mockGitHub struct {
 	conflicted map[int]bool // PRs served with mergeable=false (and, like real GitHub, a stale merge_commit_sha)
 }
 
-func newMockGitHub(t *testing.T, fixtureDir string, prs []prDef) *mockGitHub {
+// mockGitHubOption configures a mockGitHub before its server starts. The handler goroutines read these fields
+// without locking, so they must be fully populated before httptest.NewServer spawns them — setting them on the
+// returned struct afterwards is a data race the race detector flags even though the binary under test has not
+// connected yet.
+type mockGitHubOption func(*mockGitHub)
+
+// withConflicted marks the given PRs as mergeable=false.
+func withConflicted(conflicted map[int]bool) mockGitHubOption {
+	return func(m *mockGitHub) { m.conflicted = conflicted }
+}
+
+// withOpenPRs sets the list served by GET /repos/{o}/{r}/pulls for the prs command.
+func withOpenPRs(openPRs []listPR) mockGitHubOption {
+	return func(m *mockGitHub) { m.openPRs = openPRs }
+}
+
+func newMockGitHub(t *testing.T, fixtureDir string, prs []prDef, opts ...mockGitHubOption) *mockGitHub {
 	t.Helper()
 	m := &mockGitHub{fixture: fixtureDir, prs: map[int]prDef{}}
 	for _, pr := range prs {
 		m.prs[pr.number] = pr
 	}
+	for _, opt := range opts {
+		opt(m)
+	}
 	m.srv = httptest.NewServer(http.HandlerFunc(m.handle))
 	t.Cleanup(m.srv.Close)
 	return m

makefile

@@ -120,9 +120,9 @@ depscheck: ## Check that go.mod/go.sum and vendor/ are in sync
 		(echo; echo "golangci-lint version mismatch: .tools/go.mod has $$modv but .tools/.custom-gcl.yml has $$gclv - update .custom-gcl.yml to match."; exit 1)
 
 ##@ Testing
-test: build ## Run unit and integration tests
-	go test $$(go list ./... | grep -v '/integration$$') -timeout ${TEST_TIMEOUT}
-	@set -o pipefail; go test ./integration/ -v -timeout ${TEST_TIMEOUT} | grep -vE "^=== |--- PASS|^PASS$$"
+test: build ## Run unit and integration tests under the race detector
+	go test -race $$(go list ./... | grep -v '/integration$$') -timeout ${TEST_TIMEOUT}
+	@set -o pipefail; go test -race ./integration/ -v -timeout ${TEST_TIMEOUT} | grep -vE "^=== |--- PASS|^PASS$$"
 
 check-all: build test lint actionlint yamllint shellcheck depscheck ## Run build + test + all linters + depscheck