🧪 Add error handling tests for GitHub API fetching

src/lib/__tests__/github.test.ts

@@ -399,7 +399,10 @@
 
 describe("fetchActivity", () => {
   it("ヒートマップが 7×24 で初期化される", async () => {
-    mockFetch.mockResolvedValueOnce(jsonResponse(MOCK_EVENTS));
+    mockFetch
+      .mockResolvedValueOnce(jsonResponse(MOCK_EVENTS))
+      .mockResolvedValueOnce(jsonResponse([]))
+      .mockResolvedValueOnce(jsonResponse([]));
 
     const { fetchActivity } = await import("../github");
     const result = await fetchActivity("testuser", "fake-token");
@@ -411,7 +414,10 @@
   });
 
   it("イベントが正しい曜日×時間帯スロットに加算される", async () => {
-    mockFetch.mockResolvedValueOnce(jsonResponse(MOCK_EVENTS));
+    mockFetch
+      .mockResolvedValueOnce(jsonResponse(MOCK_EVENTS))
+      .mockResolvedValueOnce(jsonResponse([]))
+      .mockResolvedValueOnce(jsonResponse([]));
 
     const { fetchActivity } = await import("../github");
     const result = await fetchActivity("testuser", "fake-token");
@@ -423,7 +429,10 @@
   });
 
   it("イベント内訳がカウント順に並ぶ", async () => {
-    mockFetch.mockResolvedValueOnce(jsonResponse(MOCK_EVENTS));
+    mockFetch
+      .mockResolvedValueOnce(jsonResponse(MOCK_EVENTS))
+      .mockResolvedValueOnce(jsonResponse([]))
+      .mockResolvedValueOnce(jsonResponse([]));
 
     const { fetchActivity } = await import("../github");
     const result = await fetchActivity("testuser", "fake-token");
@@ -434,7 +443,10 @@
   });
 
   it("totalEvents がイベント総数と一致する", async () => {
-    mockFetch.mockResolvedValueOnce(jsonResponse(MOCK_EVENTS));
+    mockFetch
+      .mockResolvedValueOnce(jsonResponse(MOCK_EVENTS))
+      .mockResolvedValueOnce(jsonResponse([]))
+      .mockResolvedValueOnce(jsonResponse([]));
 
     const { fetchActivity } = await import("../github");
     const result = await fetchActivity("testuser", "fake-token");
@@ -443,7 +455,10 @@
   });
 
   it("空のイベント配列を正しく処理する", async () => {
-    mockFetch.mockResolvedValueOnce(jsonResponse([]));
+    mockFetch
+      .mockResolvedValueOnce(jsonResponse([]))
+      .mockResolvedValueOnce(jsonResponse([]))
+      .mockResolvedValueOnce(jsonResponse([]));
 
     const { fetchActivity } = await import("../github");
     const result = await fetchActivity("testuser", "fake-token");
@@ -454,6 +469,52 @@
     const totalHeatmap = result.heatmap.flat().reduce((a, b) => a + b, 0);
     expect(totalHeatmap).toBe(0);
   });
+  describe("Error handling", () => {
+    it("ユーザーが存在しない場合 UserNotFoundError をスローする", async () => {
+      mockFetch
+        .mockResolvedValueOnce(jsonResponse(null, 404))
+        .mockResolvedValueOnce(jsonResponse([]))
+        .mockResolvedValueOnce(jsonResponse([]));
+
+      const { fetchActivity } = await import("../github");
+      const { UserNotFoundError } = await import("../types");
+
+      await expect(fetchActivity("nonexistent", "fake-token")).rejects.toThrow(
+        UserNotFoundError
+      );
+    });
+
+    it("レート制限の場合 RateLimitError をスローする", async () => {
+      mockFetch
+        .mockResolvedValueOnce(
+          jsonResponse(null, 403, { "X-RateLimit-Reset": "1700000000" })
+        )
+        .mockResolvedValueOnce(jsonResponse([]))
+        .mockResolvedValueOnce(jsonResponse([]));
+
+      const { fetchActivity } = await import("../github");
+      const { RateLimitError } = await import("../types");
+
+      await expect(fetchActivity("testuser", "fake-token")).rejects.toThrow(
+        RateLimitError
+      );
+    });
+
+    it("APIエラー(500)等の場合、それまでの結果を返す(早期終了)", async () => {
+      // 1ページ目は成功、2ページ目で500エラー、3ページ目も成功(ただし無視される)
+      mockFetch
+        .mockResolvedValueOnce(jsonResponse(MOCK_EVENTS))
+        .mockResolvedValueOnce(jsonResponse(null, 500))
+        .mockResolvedValueOnce(jsonResponse([]));
+
+      const { fetchActivity } = await import("../github");
+      const result = await fetchActivity("testuser", "fake-token");
+
+      // 1ページ目のイベント(3件)が取得できているはず
+      expect(result.totalEvents).toBe(MOCK_EVENTS.length);
+      expect(result.eventBreakdown[0].type).toBe("PushEvent");
+    });
+  });
 });
 
 // ---------- fetchStarredRepos ----------
@@ -508,7 +569,7 @@
    */
   function setupUrlBasedMock() {
     // GraphQL 呼び出しカウンター (pinned → repos → contributions の順で異なるデータを返す)
     let graphqlCallCount = 0;
 
     mockFetch.mockImplementation((url: string | URL | Request, options?: RequestInit) => {
       const urlStr = typeof url === "string" ? url : url instanceof URL ? url.toString() : url.url;