test(cmd/prometheus): speed up test execution by t.Parallel() when possible

turn some loops into subtests to make use of t.Parallel()

requires Go 1.22 to make use of https://go.dev/blog/loopvar-preview

Signed-off-by: machine424 <ayoubmrini424@gmail.com>

cmd/prometheus/main_test.go

@@ -125,6 +125,7 @@ func TestFailedStartupExitCode(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping test in short mode.")
 	}
+	t.Parallel()
 
 	fakeInputFile := "fake-input-file"
 	expectedExitStatus := 2
@@ -211,9 +212,36 @@ func TestWALSegmentSizeBounds(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping test in short mode.")
 	}
+	t.Parallel()
 
-	for size, expectedExitStatus := range map[string]int{"9MB": 1, "257MB": 1, "10": 2, "1GB": 1, "12MB": 0} {
+	for _, tc := range []struct {
-		prom := exec.Command(promPath, "-test.main", "--storage.tsdb.wal-segment-size="+size, "--web.listen-address=0.0.0.0:0", "--config.file="+promConfig, "--storage.tsdb.path="+filepath.Join(t.TempDir(), "data"))
+		size     string
+		exitCode int
+	}{
+		{
+			size:     "9MB",
+			exitCode: 1,
+		},
+		{
+			size:     "257MB",
+			exitCode: 1,
+		},
+		{
+			size:     "10",
+			exitCode: 2,
+		},
+		{
+			size:     "1GB",
+			exitCode: 1,
+		},
+		{
+			size:     "12MB",
+			exitCode: 0,
+		},
+	} {
+		t.Run(tc.size, func(t *testing.T) {
+			t.Parallel()
+			prom := exec.Command(promPath, "-test.main", "--storage.tsdb.wal-segment-size="+tc.size, "--web.listen-address=0.0.0.0:0", "--config.file="+promConfig, "--storage.tsdb.path="+filepath.Join(t.TempDir(), "data"))
 
 			// Log stderr in case of failure.
 			stderr, err := prom.StderrPipe()
@@ -226,7 +254,7 @@ func TestWALSegmentSizeBounds(t *testing.T) {
 			err = prom.Start()
 			require.NoError(t, err)
 
-		if expectedExitStatus == 0 {
+			if tc.exitCode == 0 {
 				done := make(chan error, 1)
 				go func() { done <- prom.Wait() }()
 				select {
@@ -236,7 +264,7 @@ func TestWALSegmentSizeBounds(t *testing.T) {
 					prom.Process.Kill()
 					<-done
 				}
-			continue
+				return
 			}
 
 			err = prom.Wait()
@@ -244,19 +272,33 @@ func TestWALSegmentSizeBounds(t *testing.T) {
 			var exitError *exec.ExitError
 			require.ErrorAs(t, err, &exitError)
 			status := exitError.Sys().(syscall.WaitStatus)
-		require.Equal(t, expectedExitStatus, status.ExitStatus())
+			require.Equal(t, tc.exitCode, status.ExitStatus())
+		})
 	}
 }
 
 func TestMaxBlockChunkSegmentSizeBounds(t *testing.T) {
-	t.Parallel()
-
 	if testing.Short() {
 		t.Skip("skipping test in short mode.")
 	}
+	t.Parallel()
 
-	for size, expectedExitStatus := range map[string]int{"512KB": 1, "1MB": 0} {
+	for _, tc := range []struct {
-		prom := exec.Command(promPath, "-test.main", "--storage.tsdb.max-block-chunk-segment-size="+size, "--web.listen-address=0.0.0.0:0", "--config.file="+promConfig, "--storage.tsdb.path="+filepath.Join(t.TempDir(), "data"))
+		size     string
+		exitCode int
+	}{
+		{
+			size:     "512KB",
+			exitCode: 1,
+		},
+		{
+			size:     "1MB",
+			exitCode: 0,
+		},
+	} {
+		t.Run(tc.size, func(t *testing.T) {
+			t.Parallel()
+			prom := exec.Command(promPath, "-test.main", "--storage.tsdb.max-block-chunk-segment-size="+tc.size, "--web.listen-address=0.0.0.0:0", "--config.file="+promConfig, "--storage.tsdb.path="+filepath.Join(t.TempDir(), "data"))
 
 			// Log stderr in case of failure.
 			stderr, err := prom.StderrPipe()
@@ -269,7 +311,7 @@ func TestMaxBlockChunkSegmentSizeBounds(t *testing.T) {
 			err = prom.Start()
 			require.NoError(t, err)
 
-		if expectedExitStatus == 0 {
+			if tc.exitCode == 0 {
 				done := make(chan error, 1)
 				go func() { done <- prom.Wait() }()
 				select {
@@ -279,7 +321,7 @@ func TestMaxBlockChunkSegmentSizeBounds(t *testing.T) {
 					prom.Process.Kill()
 					<-done
 				}
-			continue
+				return
 			}
 
 			err = prom.Wait()
@@ -287,7 +329,8 @@ func TestMaxBlockChunkSegmentSizeBounds(t *testing.T) {
 			var exitError *exec.ExitError
 			require.ErrorAs(t, err, &exitError)
 			status := exitError.Sys().(syscall.WaitStatus)
-		require.Equal(t, expectedExitStatus, status.ExitStatus())
+			require.Equal(t, tc.exitCode, status.ExitStatus())
+		})
 	}
 }
 
@@ -353,6 +396,8 @@ func getCurrentGaugeValuesFor(t *testing.T, reg prometheus.Gatherer, metricNames
 }
 
 func TestAgentSuccessfulStartup(t *testing.T) {
+	t.Parallel()
+
 	prom := exec.Command(promPath, "-test.main", "--agent", "--web.listen-address=0.0.0.0:0", "--config.file="+agentConfig)
 	require.NoError(t, prom.Start())
 
@@ -371,6 +416,8 @@ func TestAgentSuccessfulStartup(t *testing.T) {
 }
 
 func TestAgentFailedStartupWithServerFlag(t *testing.T) {
+	t.Parallel()
+
 	prom := exec.Command(promPath, "-test.main", "--agent", "--storage.tsdb.path=.", "--web.listen-address=0.0.0.0:0", "--config.file="+promConfig)
 
 	output := bytes.Buffer{}
@@ -398,6 +445,8 @@ func TestAgentFailedStartupWithServerFlag(t *testing.T) {
 }
 
 func TestAgentFailedStartupWithInvalidConfig(t *testing.T) {
+	t.Parallel()
+
 	prom := exec.Command(promPath, "-test.main", "--agent", "--web.listen-address=0.0.0.0:0", "--config.file="+promConfig)
 	require.NoError(t, prom.Start())
 
@@ -419,6 +468,7 @@ func TestModeSpecificFlags(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping test in short mode.")
 	}
+	t.Parallel()
 
 	testcases := []struct {
 		mode       string
@@ -433,6 +483,7 @@ func TestModeSpecificFlags(t *testing.T) {
 
 	for _, tc := range testcases {
 		t.Run(fmt.Sprintf("%s mode with option %s", tc.mode, tc.arg), func(t *testing.T) {
+			t.Parallel()
 			args := []string{"-test.main", tc.arg, t.TempDir(), "--web.listen-address=0.0.0.0:0"}
 
 			if tc.mode == "agent" {
@@ -484,6 +535,8 @@ func TestDocumentation(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		t.SkipNow()
 	}
+	t.Parallel()
+
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
@@ -508,6 +561,8 @@ func TestDocumentation(t *testing.T) {
 }
 
 func TestRwProtoMsgFlagParser(t *testing.T) {
+	t.Parallel()
+
 	defaultOpts := config.RemoteWriteProtoMsgs{
 		config.RemoteWriteProtoMsgV1, config.RemoteWriteProtoMsgV2,
 	}

cmd/prometheus/main_unix_test.go

@@ -34,6 +34,7 @@ func TestStartupInterrupt(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping test in short mode.")
 	}
+	t.Parallel()
 
 	port := fmt.Sprintf(":%d", testutil.RandomUnprivilegedPort(t))
 

cmd/prometheus/query_log_test.go

@@ -456,6 +456,7 @@ func TestQueryLog(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping test in short mode.")
 	}
+	t.Parallel()
 
 	cwd, err := os.Getwd()
 	require.NoError(t, err)
@@ -474,6 +475,7 @@ func TestQueryLog(t *testing.T) {
 					}
 
 					t.Run(p.String(), func(t *testing.T) {
+						t.Parallel()
 						p.run(t)
 					})
 				}