add basic test

coder · sreya · Nov 25, 2024 · Oct 23, 2024 · Nov 18, 2024 · Nov 18, 2024
commit 00c9cd71721842df30f4c52015b54dd11b80336f
diff --git a/agent/agentexec/cli.go b/agent/agentexec/cli.go
@@ -1,7 +1,6 @@
 package agentexec
 
 import (
-	"context"
 	"fmt"
 	"os"
 	"os/exec"
@@ -20,7 +19,7 @@
 )
 
 // CLI runs the agent-exec command. It should only be called by the cli package.
-func CLI(ctx context.Context, args []string, environ []string) error {
+func CLI(args []string, environ []string) error {
 	if runtime.GOOS != "linux" {
 		return xerrors.Errorf("agent-exec is only supported on Linux")
 	}
@@ -42,7 +41,7 @@
 		return xerrors.Errorf("invalid nice score: %w", err)
 	}

 	err = syscall.Setpriority(syscall.PRIO_PROCESS, pid, score)
 	if err != nil {
 		return xerrors.Errorf("set nice score: %w", err)
 	}

diff --git a/agent/agentexec/cli_test.go b/agent/agentexec/cli_test.go
@@ -0,0 +1,90 @@
+package agentexec_test
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+	"syscall"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"golang.org/x/sys/unix"
+
+	"github.com/coder/coder/v2/testutil"
+)
+
+func TestCLI(t *testing.T) {
+	t.Parallel()
+	t.Run("OK", func(t *testing.T) {
+		t.Parallel()
+
+		ctx := testutil.Context(t, testutil.WaitMedium)
+		cmd, dir := cmd(t, ctx)
+		cmd.Env = append(cmd.Env, "CODER_PROC_NICE_SCORE=10")
+		cmd.Env = append(cmd.Env, "CODER_PROC_OOM_SCORE=123")
+		err := cmd.Start()
+		require.NoError(t, err)
+
+		waitForSentinel(t, ctx, cmd, dir)
+		requireOOMScore(t, cmd.Process.Pid, 123)
+		requireNiceScore(t, cmd.Process.Pid, 10)
+	})
+}
+
+func requireNiceScore(t *testing.T, pid int, score int) {
+	t.Helper()
+
+	nice, err := unix.Getpriority(0, pid)
+	require.NoError(t, err)
+	require.Equal(t, score, nice)
+}
+
+func requireOOMScore(t *testing.T, pid int, expected int) {
+	t.Helper()
+
+	actual, err := os.ReadFile(fmt.Sprintf("/proc/%d/oom_score_adj", pid))
+	require.NoError(t, err)
+	score := strings.TrimSpace(string(actual))
+	require.Equal(t, strconv.Itoa(expected), score)
+}
+
+func waitForSentinel(t *testing.T, ctx context.Context, cmd *exec.Cmd, dir string) {
+	t.Helper()
+
+	require.Eventually(t, func() bool {
+		// Check if the process is still running.
+		err := cmd.Process.Signal(syscall.Signal(0))
+		require.NoError(t, err)
+
+		_, err = os.Stat(dir)
+		return err == nil && ctx.Err() == nil
+	}, testutil.WaitLong, testutil.IntervalFast)
+}
+
+func cmd(t *testing.T, ctx context.Context, args ...string) (*exec.Cmd, string) {
+	dir := ""
+	cmd := exec.Command(TestBin, args...)
+	if len(args) == 0 {
+		dir = t.TempDir()
+		//nolint:gosec
+		cmd = exec.CommandContext(ctx, TestBin, "sh", "-c", fmt.Sprintf("touch %s && sleep 10m", dir))
+	}
+	var buf bytes.Buffer
+	cmd.Stdout = &buf
+	cmd.Stderr = &buf
+	t.Cleanup(func() {
+		// Print output of a command if the test fails.
+		if t.Failed() {
+			t.Logf("cmd %q output: %s", cmd.Args, buf.String())
+		}
+
+		if cmd.Process != nil {
+			_ = cmd.Process.Kill()
+		}
+	})
+	return cmd, dir
+}
diff --git a/agent/agentexec/cmdtest/main.go b/agent/agentexec/cmdtest/main.go
@@ -1,15 +1,14 @@
 package main
 
 import (
-	"context"
 	"fmt"
 	"os"
 
 	"github.com/coder/coder/v2/agent/agentexec"
 )
 
 func main() {
-	err := agentexec.CLI(context.Background(), os.Args, os.Environ())
+	err := agentexec.CLI(os.Args, os.Environ())
 	if err != nil {
 		_, _ = fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)

diff --git a/agent/agentexec/main_test.go b/agent/agentexec/main_test.go
@@ -0,0 +1,27 @@
+package agentexec_test
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"testing"
+)
+
+const TestBin = "/tmp/agent-test"
+
+func TestMain(m *testing.M) {
+	buildBinary()
+
+	os.Exit(m.Run())
+}
+
+func buildBinary() {
+	out, err := exec.Command("go", "build", "-o", TestBin, "./cmdtest").CombinedOutput()
+	mustf(err, "build binary: %s", out)
+}
+
+func mustf(err error, msg string, args ...any) {
+	if err != nil {
+		panic(fmt.Sprintf(msg, args...))
+	}
+}