make e2e more safe to run

Author: SamMorrowDrums

e2e/README.md

@@ -83,6 +83,18 @@ It is possible to provide `GITHUB_MCP_SERVER_E2E_DEBUG=true` to run the e2e test
 
 One might argue that the lack of visibility into failures for the black box tests also indicates a product need, but this solves for the immediate pain point felt as a maintainer.
 
+## Skipping Global State Mutation Tests
+
+Some tools (such as those that mark all notifications as read) will change the real global state of the authenticated user. For end-to-end (e2e) tests, these tests are **skipped by default** to avoid unwanted side effects.
+
+To opt-in and run these tests (which will modify your global state on GitHub), set the following environment variable:
+
+```
+GITHUB_MCP_SERVER_E2E_MUTATE_GLOBAL_STATE=1
+```
+
+If this variable is not set, tests that would mutate global state will be skipped.
+
 ## Limitations
 
 The current test suite is intentionally very limited in scope. This is because the maintenance costs on e2e tests tend to increase significantly over time. To read about some challenges with GitHub integration tests, see [go-github integration tests README](https://github.com/google/go-github/blob/5b75aa86dba5cf4af2923afa0938774f37fa0a67/test/README.md). We will expand this suite circumspectly!

e2e/e2e_test.go

@@ -24,6 +24,16 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+// Should be set to opt-in to tests that mutate global state
+const E2EGlobalMutationOptInEnv = "GITHUB_MCP_SERVER_E2E_MUTATE_GLOBAL_STATE"
+
+// skipIfGlobalMutationNotOptedIn skips the test if the opt-in env var is not set
+func skipIfGlobalMutationNotOptedIn(t *testing.T) {
+	if os.Getenv(E2EGlobalMutationOptInEnv) == "" {
+		t.Skipf("Skipping test: set %s=1 to opt-in to global state mutation tests", E2EGlobalMutationOptInEnv)
+	}
+}
+
 var (
 	// Shared variables and sync.Once instances to ensure one-time execution
 	getTokenOnce sync.Once
@@ -1550,6 +1560,7 @@ func TestE2E_ListNotifications(t *testing.T) {
 }
 
 func TestE2E_ManageNotificationSubscription(t *testing.T) {
+	skipIfGlobalMutationNotOptedIn(t)
 	t.Parallel()
 	client := setupMCPClient(t)
 	ctx := context.Background()
@@ -1561,9 +1572,7 @@ func TestE2E_ManageNotificationSubscription(t *testing.T) {
 	resp, err := client.CallTool(ctx, listReq)
 	require.NoError(t, err)
 	require.False(t, resp.IsError)
-	if len(resp.Content) == 0 {
-		return t.Skip("No notifications available to test subscription management")
-	}
+
 	textContent, ok := resp.Content[0].(mcp.TextContent)
 	require.True(t, ok)
 	var notifications []struct {
@@ -1572,6 +1581,9 @@ func TestE2E_ManageNotificationSubscription(t *testing.T) {
 	err = json.Unmarshal([]byte(textContent.Text), &notifications)
 	require.NoError(t, err)
 	require.NotEmpty(t, notifications)
+	if len(notifications) == 0 {
+		t.Skip("No notifications available to test subscription management")
+	}
 	notificationID := notifications[0].ID
 
 	// Ignore notification
@@ -1618,6 +1630,7 @@ func TestE2E_ManageNotificationSubscription(t *testing.T) {
 }
 
 func TestE2E_ManageRepositoryNotificationSubscription(t *testing.T) {
+	skipIfGlobalMutationNotOptedIn(t)
 	t.Parallel()
 	client := setupMCPClient(t)
 	ctx := context.Background()
@@ -1673,6 +1686,7 @@ func TestE2E_ManageRepositoryNotificationSubscription(t *testing.T) {
 }
 
 func TestE2E_DismissNotification(t *testing.T) {
+	skipIfGlobalMutationNotOptedIn(t)
 	t.Parallel()
 	client := setupMCPClient(t)
 	ctx := context.Background()
@@ -1684,16 +1698,16 @@ func TestE2E_DismissNotification(t *testing.T) {
 	resp, err := client.CallTool(ctx, listReq)
 	require.NoError(t, err)
 	require.False(t, resp.IsError)
-	if len(resp.Content) == 0 {
-		return t.Skip("No notifications available to test dismissal")
-	}
 	textContent, ok := resp.Content[0].(mcp.TextContent)
 	require.True(t, ok)
 	var notifications []struct {
 		ID string `json:"id"`
 	}
 	err = json.Unmarshal([]byte(textContent.Text), &notifications)
 	require.NoError(t, err)
+	if len(notifications) == 0 {
+		t.Skip("No notifications available to test dismissal")
+	}
 	require.NotEmpty(t, notifications)
 	threadID := notifications[0].ID
 
@@ -1713,6 +1727,7 @@ func TestE2E_DismissNotification(t *testing.T) {
 }
 
 func TestE2E_MarkAllNotificationsRead(t *testing.T) {
+	skipIfGlobalMutationNotOptedIn(t)
 	t.Parallel()
 	client := setupMCPClient(t)
 	ctx := context.Background()