fix(github): add DismissReview Event comment; use t.Fatalf for routing assertions

- Add comment in DismissReview explaining why the Event field is required
  by the GitHub API even though DISMISS is the only valid value (#18652).
- Change t.Errorf to t.Fatalf for method/path routing assertions in test
  handlers so failures are immediately fatal instead of silently
  continuing handler execution (#18653).

github/review.go

@@ -194,7 +194,9 @@ func (c *Client) DismissReview(ctx context.Context, owner, repo string, number i
 
 	payload := dismissReviewRequest{
 		Message: message,
-		Event:   "DISMISS",
+		// Event is required by the GitHub API for dismissal requests, even though
+		// "DISMISS" is the only valid value for this endpoint.
+		Event: "DISMISS",
 	}
 
 	data, err := json.Marshal(payload)

github/review_test.go

@@ -17,10 +17,10 @@ import (
 func TestPostReview_HappyPath(t *testing.T) {
 	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != "POST" {
-			t.Errorf("expected POST, got %s", r.Method)
+			t.Fatalf("expected POST, got %s", r.Method)
 		}
 		if r.URL.Path != "/repos/owner/repo/pulls/5/reviews" {
-			t.Errorf("unexpected path: %s", r.URL.Path)
+			t.Fatalf("unexpected path: %s", r.URL.Path)
 		}
 		if r.Header.Get("Content-Type") != "application/json" {
 			t.Errorf("expected Content-Type application/json, got %q", r.Header.Get("Content-Type"))
@@ -150,10 +150,10 @@ func TestPostReview_MalformedResponse(t *testing.T) {
 func TestListReviews_HappyPath(t *testing.T) {
 	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != "GET" {
-			t.Errorf("expected GET, got %s", r.Method)
+			t.Fatalf("expected GET, got %s", r.Method)
 		}
 		if r.URL.Path != "/repos/owner/repo/pulls/3/reviews" {
-			t.Errorf("unexpected path: %s", r.URL.Path)
+			t.Fatalf("unexpected path: %s", r.URL.Path)
 		}
 		json.NewEncoder(w).Encode([]map[string]interface{}{
 			{
@@ -250,10 +250,10 @@ func TestListReviews_401(t *testing.T) {
 func TestDeleteReview_HappyPath(t *testing.T) {
 	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != "DELETE" {
-			t.Errorf("expected DELETE, got %s", r.Method)
+			t.Fatalf("expected DELETE, got %s", r.Method)
 		}
 		if r.URL.Path != "/repos/owner/repo/pulls/5/reviews/42" {
-			t.Errorf("unexpected path: %s", r.URL.Path)
+			t.Fatalf("unexpected path: %s", r.URL.Path)
 		}
 		w.WriteHeader(204)
 	})
@@ -284,10 +284,10 @@ func TestDeleteReview_422_SubmittedReview(t *testing.T) {
 func TestDismissReview_HappyPath(t *testing.T) {
 	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != "PUT" {
-			t.Errorf("expected PUT, got %s", r.Method)
+			t.Fatalf("expected PUT, got %s", r.Method)
 		}
 		if r.URL.Path != "/repos/owner/repo/pulls/5/reviews/10/dismissals" {
-			t.Errorf("unexpected path: %s", r.URL.Path)
+			t.Fatalf("unexpected path: %s", r.URL.Path)
 		}
 
 		body, _ := io.ReadAll(r.Body)