diff --git a/frontend/src/app/common/service/gmail/gmail.service.spec.ts b/frontend/src/app/common/service/gmail/gmail.service.spec.ts
index fd4ce18ca72..08ee8f09bb5 100644
--- a/frontend/src/app/common/service/gmail/gmail.service.spec.ts
+++ b/frontend/src/app/common/service/gmail/gmail.service.spec.ts
@@ -39,6 +39,7 @@ describe("GmailService", () => {
 
   afterEach(() => {
     httpTestingController.verify();
+    vi.restoreAllMocks();
   });
 
   it("should show a success toast when the backend accepts the send request", () => {
@@ -51,16 +52,77 @@ describe("GmailService", () => {
     expect(notificationSpy.error).not.toHaveBeenCalled();
   });
 
-  it("should show an error toast when the backend returns an HTTP error (e.g. SMTP failure)", () => {
+  it("sends the correct PUT body for sendEmail with an explicit receiver", () => {
     service.sendEmail("subj", "body", "to@example.com");
 
     const req = httpTestingController.expectOne(r => r.url.endsWith("/gmail/send") && r.method === "PUT");
-    req.flush("Failed to send email: 535-5.7.8 Username and Password not accepted", {
-      status: 502,
-      statusText: "Bad Gateway",
-    });
+    expect(req.request.body).toEqual({ receiver: "to@example.com", subject: "subj", content: "body" });
+    req.flush(null);
+  });
+
+  it("defaults the receiver to an empty string when it is omitted", () => {
+    service.sendEmail("subj", "body");
+
+    const req = httpTestingController.expectOne(r => r.url.endsWith("/gmail/send") && r.method === "PUT");
+    expect(req.request.body).toEqual({ receiver: "", subject: "subj", content: "body" });
+    req.flush(null);
+  });
+
+  it("shows an error toast and logs to the console on a failed send", () => {
+    const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    service.sendEmail("subj", "body", "to@example.com");
+
+    const req = httpTestingController.expectOne(r => r.url.endsWith("/gmail/send") && r.method === "PUT");
+    req.flush("boom", { status: 502, statusText: "Bad Gateway" });
 
     expect(notificationSpy.error).toHaveBeenCalledWith("Failed to send email. Please try again or contact admin.");
     expect(notificationSpy.success).not.toHaveBeenCalled();
+    expect(consoleSpy).toHaveBeenCalledWith("Send email error:", "boom");
+  });
+
+  it("issues a GET to the sender-email endpoint and emits the response without notifying", () => {
+    let emitted: string | undefined;
+    service.getSenderEmail().subscribe(value => (emitted = value as string));
+
+    const req = httpTestingController.expectOne(
+      r => r.url.endsWith("/gmail/sender/email") && r.method === "GET" && r.responseType === "text"
+    );
+    req.flush("sender@example.com");
+
+    expect(emitted).toBe("sender@example.com");
+    expect(notificationSpy.success).not.toHaveBeenCalled();
+    expect(notificationSpy.error).not.toHaveBeenCalled();
+  });
+
+  it("sends the correct POST body for notifyUnauthorizedLogin", () => {
+    service.notifyUnauthorizedLogin("u@example.com", "ACME", "for research");
+
+    const req = httpTestingController.expectOne(
+      r => r.url.endsWith("/gmail/notify-unauthorized") && r.method === "POST"
+    );
+    expect(req.request.body).toEqual({ receiver: "u@example.com", affiliation: "ACME", reason: "for research" });
+    req.flush(null);
+  });
+
+  it("shows a success toast when the unauthorized-login notification is accepted", () => {
+    service.notifyUnauthorizedLogin("u@example.com", "ACME", "for research");
+
+    httpTestingController
+      .expectOne(r => r.url.endsWith("/gmail/notify-unauthorized") && r.method === "POST")
+      .flush(null);
+
+    expect(notificationSpy.success).toHaveBeenCalledWith("An admin has been notified about your account request.");
+  });
+
+  it("shows an error toast and logs to the console when the notification fails", () => {
+    const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    service.notifyUnauthorizedLogin("u@example.com", "ACME", "for research");
+
+    httpTestingController
+      .expectOne(r => r.url.endsWith("/gmail/notify-unauthorized") && r.method === "POST")
+      .flush("boom", { status: 500, statusText: "Internal Server Error" });
+
+    expect(notificationSpy.error).toHaveBeenCalledWith("Failed to notify admin about your account request.");
+    expect(consoleSpy).toHaveBeenCalledWith("Notify error:", "boom");
   });
 });