Merge pull request #635 from jfly/fix-flaky-tests

chore: fix flaky tests

Author: brianmcgee

cmd/root_test.go

@@ -1382,7 +1382,6 @@ func TestGit(t *testing.T) {
 	as.NoError(gitCmd.Run(), "failed to add everything to the index")
 
 	treefmt(t,
-		withConfig(configPath, cfg),
 		withNoError(t),
 		withStats(t, map[stats.Type]int{
 			stats.Traversed: 33,
@@ -1401,7 +1400,6 @@ func TestGit(t *testing.T) {
 	})
 
 	treefmt(t,
-		withConfig(configPath, cfg),
 		withNoError(t),
 		withStats(t, map[stats.Type]int{
 			stats.Traversed: 33,
@@ -1417,7 +1415,6 @@ func TestGit(t *testing.T) {
 	// we should traverse and match against fewer files, but no formatting should occur as no formatting signatures
 	// are impacted
 	treefmt(t,
-		withConfig(configPath, cfg),
 		withNoError(t),
 		withStats(t, map[stats.Type]int{
 			stats.Traversed: 30,
@@ -1436,7 +1433,6 @@ func TestGit(t *testing.T) {
 	// traverse 82 files.
 	treefmt(t,
 		withArgs("--walk", "filesystem"),
-		withConfig(configPath, cfg),
 		withNoError(t),
 		withStats(t, map[stats.Type]int{
 			stats.Traversed: 82,
@@ -1605,7 +1601,6 @@ func TestJujutsu(t *testing.T) {
 	})
 
 	treefmt(t,
-		withConfig(configPath, cfg),
 		withNoError(t),
 		withStats(t, map[stats.Type]int{
 			stats.Traversed: 33,
@@ -1625,7 +1620,6 @@ func TestJujutsu(t *testing.T) {
 	// we should traverse and match against fewer files, but no formatting should occur as no formatting signatures
 	// are impacted
 	treefmt(t,
-		withConfig(configPath, cfg),
 		withNoError(t),
 		withStats(t, map[stats.Type]int{
 			stats.Traversed: 30,
@@ -1644,7 +1638,6 @@ func TestJujutsu(t *testing.T) {
 	// traverse 130 files.
 	treefmt(t,
 		withArgs("--walk", "filesystem"),
-		withConfig(configPath, cfg),
 		withNoError(t),
 		withStats(t, map[stats.Type]int{
 			stats.Traversed: 133,

test/test.go

@@ -28,6 +28,16 @@ func SetenvXdgConfigDir(t *testing.T) {
 func WriteConfig(t *testing.T, path string, cfg *config.Config) {
 	t.Helper()
 
+	oldInfo, err := os.Lstat(path)
+
+	switch {
+	case os.IsNotExist(err):
+		// It's fine if there was no old config file, the new file is guaranteed to appear new =)
+		oldInfo = nil
+	case err != nil:
+		t.Fatalf("failed to stat old config file: %v", path)
+	}
+
 	f, err := os.Create(path)
 	if err != nil {
 		t.Fatalf("failed to create a new config file: %v", err)
@@ -37,6 +47,30 @@ func WriteConfig(t *testing.T, path string, cfg *config.Config) {
 	if err = encoder.Encode(cfg); err != nil {
 		t.Fatalf("failed to write to config file: %v", err)
 	}
+
+	// Ensure the modtime of the config file always increases
+	// (even if this requires setting it to the future!)
+	// If we don't do this, we end up with flaky tests that behave differently
+	// depending on if they run quickly enough for the modtime to stay constant throughout the test.
+	newInfo, err := os.Lstat(path)
+	if err != nil {
+		t.Fatalf("failed to create a new config file: %v", err)
+	}
+	// Note: we're comparing `Unix()` (which is only 1 second granularity) for consistency with
+	// `walk.go::formatSignature`.
+	if oldInfo != nil && oldInfo.ModTime().Unix() == newInfo.ModTime().Unix() {
+		// Ideally we wouldn't change the atime at all, but it's hard to fetch
+		// the original atime in a cross-platform manner.
+		newAtime := time.Now()
+
+		// Increase the mtime so it's different.
+		newMtime := oldInfo.ModTime().Add(time.Second)
+
+		err = Lutimes(t, path, newAtime, newMtime)
+		if err != nil {
+			t.Fatalf("failed to change file times: %v", err)
+		}
+	}
 }
 
 func TempExamples(t *testing.T) string {