test(frontend): enhance AdminUserApprovalComponent tests with full coverage

Add comprehensive tests covering:
- Tab navigation (pending/all) with signal verification
- loadAllUsers() calls correct endpoint via generated AdminIAMService
- Error handling for loadPendingUsers and loadAllUsers failures
- Approve/reject user actions including undefined userId guards
- Template rendering: pending tab with Freigeben/Ablehnen buttons
- Template rendering: all users tab without action buttons
- Status badge rendering in both tabs
- Role column display (Unternehmen/Privatperson)
- Empty state messages for both tabs
- Duplicate Status column header bug fix verification
- No reload of allUsers if already loaded

eeg_frontend/src/app/pages/admin-user-approval/admin-user-approval.spec.ts

@@ -82,16 +82,14 @@ describe('AdminUserApprovalComponent', () => {
     expect(component.pendingUsers()[0].firstName).toBe('Max');
   });
 
-  it('should load all users when switching to all tab', () => {
+  it('should load all users via getAllUsers endpoint when switching to all tab', () => {
     fixture.detectChanges();
     const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
     pendingReq.flush([]);
 
     component.switchTab('all');
 
-    const allReq = httpMock.expectOne(
+    const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
-      (r) => r.url.includes('/admin/users') && !r.url.includes('/pending'),
-    );
     expect(allReq.request.method).toBe('GET');
     allReq.flush([mockPendingUser, mockApprovedUser, mockRejectedUser]);
 
@@ -104,9 +102,7 @@ describe('AdminUserApprovalComponent', () => {
     req.flush([]);
 
     component.switchTab('all');
-    const allReq = httpMock.expectOne(
+    const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
-      (r) => r.url.includes('/admin/users') && !r.url.includes('/pending'),
-    );
     allReq.flush([]);
     expect(component.activeTab()).toBe('all');
 
@@ -114,6 +110,49 @@ describe('AdminUserApprovalComponent', () => {
     expect(component.activeTab()).toBe('pending');
   });
 
+  it('should not reload all users if already loaded', () => {
+    fixture.detectChanges();
+    const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+    pendingReq.flush([]);
+
+    component.switchTab('all');
+    const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
+    allReq.flush([mockApprovedUser]);
+    fixture.detectChanges();
+
+    component.switchTab('pending');
+    expect(component.activeTab()).toBe('pending');
+
+    component.switchTab('all');
+    expect(component.activeTab()).toBe('all');
+    const allReqs = httpMock.match((r) => r.url === '/api/admin/users');
+    expect(allReqs.length).toBe(1);
+  });
+
+  it('should set error message when loadPendingUsers fails', () => {
+    fixture.detectChanges();
+    const req = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+    req.flush('Error', { status: 500, statusText: 'Server Error' });
+
+    expect(component.errorMessage()).toBe(
+      'Fehler beim Laden der Daten aus dem EDA-Netz-Check.',
+    );
+    expect(component.isLoading()).toBe(false);
+  });
+
+  it('should set error message when loadAllUsers fails', () => {
+    fixture.detectChanges();
+    const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+    pendingReq.flush([]);
+
+    component.switchTab('all');
+    const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
+    allReq.flush('Error', { status: 500, statusText: 'Server Error' });
+
+    expect(component.errorMessage()).toBe('Fehler beim Laden aller Benutzer.');
+    expect(component.isLoading()).toBe(false);
+  });
+
   describe('getStatusLabel', () => {
     it('should return "Ausstehend" for PENDING', () => {
       expect(component.getStatusLabel('PENDING')).toBe('Ausstehend');
@@ -175,6 +214,17 @@ describe('AdminUserApprovalComponent', () => {
     expect(component.pendingUsers().length).toBe(0);
   });
 
+  it('should not call API when approveUser has undefined userId', () => {
+    fixture.detectChanges();
+    const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+    pendingReq.flush([]);
+
+    component.approveUser(undefined);
+
+    const approveReqs = httpMock.match((r) => r.url.includes('/approve'));
+    expect(approveReqs.length).toBe(0);
+  });
+
   it('should reject user and remove from pending list', () => {
     fixture.detectChanges();
     const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
@@ -188,8 +238,45 @@ describe('AdminUserApprovalComponent', () => {
     expect(component.pendingUsers().length).toBe(0);
   });
 
+  it('should not call API when rejectUser has undefined id', () => {
+    fixture.detectChanges();
+    const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+    pendingReq.flush([]);
+
+    component.rejectUser({ ...mockPendingUser, id: undefined });
+
+    const rejectReqs = httpMock.match((r) => r.url.includes('/reject'));
+    expect(rejectReqs.length).toBe(0);
+  });
+
+  it('should show error message when approveUser fails', () => {
+    fixture.detectChanges();
+    const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+    pendingReq.flush([mockPendingUser]);
+
+    vi.spyOn(window, 'confirm').mockReturnValue(true);
+    component.approveUser(mockPendingUser.id);
+
+    const approveReq = httpMock.expectOne((r) => r.url.includes('/approve'));
+    approveReq.flush('Error', { status: 500, statusText: 'Server Error' });
+
+    expect(component.errorMessage()).toBe('Der User konnte nicht freigegeben werden.');
+  });
+
+  it('should show error toast when rejectUser fails', () => {
+    fixture.detectChanges();
+    const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+    pendingReq.flush([mockPendingUser]);
+
+    vi.spyOn(window, 'confirm').mockReturnValue(true);
+    component.rejectUser(mockPendingUser);
+
+    const rejectReq = httpMock.expectOne((r) => r.url.includes('/reject'));
+    rejectReq.flush({ message: 'Ablehnung fehlgeschlagen' }, { status: 500, statusText: 'Server Error' });
+  });
+
   describe('template', () => {
-    it('should render tab navigation', () => {
+    it('should render tab navigation with two tabs', () => {
       fixture.detectChanges();
       const req = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
       req.flush([]);
@@ -211,7 +298,7 @@ describe('AdminUserApprovalComponent', () => {
       expect(activeTab?.textContent).toContain('Ausstehende Anträge');
     });
 
-    it('should show only one Status column header (no duplicate)', () => {
+    it('should show only one Status column header in pending tab (no duplicate)', () => {
       fixture.detectChanges();
       const req = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
       req.flush([mockPendingUser]);
@@ -226,5 +313,142 @@ describe('AdminUserApprovalComponent', () => {
       }
       expect(statusCount).toBe(1);
     });
+
+    it('should show pending users table with Freigeben and Ablehnen buttons', () => {
+      fixture.detectChanges();
+      const req = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+      req.flush([mockPendingUser]);
+      fixture.detectChanges();
+
+      const table = fixture.nativeElement.querySelector('table');
+      expect(table).toBeTruthy();
+      const rows = fixture.nativeElement.querySelectorAll('tbody tr');
+      expect(rows.length).toBe(1);
+
+      const buttons = rows[0].querySelectorAll('button');
+      expect(buttons.length).toBe(2);
+      expect(buttons[0].textContent?.trim()).toBe('Freigeben');
+      expect(buttons[1].textContent?.trim()).toBe('Ablehnen');
+    });
+
+    it('should show empty state message when no pending users', () => {
+      fixture.detectChanges();
+      const req = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+      req.flush([]);
+      fixture.detectChanges();
+
+      const emptyMsg = fixture.nativeElement.querySelector('.bg-gray-50 p');
+      expect(emptyMsg?.textContent).toContain(
+        'Aktuell gibt es keine neuen User im Status PENDING',
+      );
+    });
+
+    it('should show all users table without action buttons', () => {
+      fixture.detectChanges();
+      const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+      pendingReq.flush([]);
+
+      component.switchTab('all');
+      const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
+      allReq.flush([mockApprovedUser]);
+      fixture.detectChanges();
+
+      const table = fixture.nativeElement.querySelector('table');
+      expect(table).toBeTruthy();
+      const rows = fixture.nativeElement.querySelectorAll('tbody tr');
+      expect(rows.length).toBe(1);
+
+      const buttons = rows[0].querySelectorAll('button');
+      expect(buttons.length).toBe(0);
+    });
+
+    it('should show empty state when no users exist', () => {
+      fixture.detectChanges();
+      const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+      pendingReq.flush([]);
+
+      component.switchTab('all');
+      const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
+      allReq.flush([]);
+      fixture.detectChanges();
+
+      const emptyMsg = fixture.nativeElement.querySelector('.bg-gray-50 p');
+      expect(emptyMsg?.textContent).toContain('Keine Benutzer vorhanden');
+    });
+
+    it('should display role as Unternehmen for Company participant type', () => {
+      fixture.detectChanges();
+      const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+      pendingReq.flush([]);
+
+      component.switchTab('all');
+      const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
+      allReq.flush([mockApprovedUser]);
+      fixture.detectChanges();
+
+      const rows = fixture.nativeElement.querySelectorAll('tbody tr');
+      const roleCell = rows[0].querySelectorAll('td')[2];
+      expect(roleCell?.textContent?.trim()).toBe('Unternehmen');
+    });
+
+    it('should display role as Privatperson for Private participant type', () => {
+      fixture.detectChanges();
+      const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+      pendingReq.flush([]);
+
+      component.switchTab('all');
+      const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
+      allReq.flush([mockRejectedUser]);
+      fixture.detectChanges();
+
+      const rows = fixture.nativeElement.querySelectorAll('tbody tr');
+      const roleCell = rows[0].querySelectorAll('td')[2];
+      expect(roleCell?.textContent?.trim()).toBe('Privatperson');
+    });
+
+    it('should show status badge in pending users table', () => {
+      fixture.detectChanges();
+      const req = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+      req.flush([mockPendingUser]);
+      fixture.detectChanges();
+
+      const badge = fixture.nativeElement.querySelector('span.rounded-full');
+      expect(badge?.textContent?.trim()).toBe('Ausstehend');
+    });
+
+    it('should show status badge in all users table', () => {
+      fixture.detectChanges();
+      const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+      pendingReq.flush([]);
+
+      component.switchTab('all');
+      const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
+      allReq.flush([mockApprovedUser]);
+      fixture.detectChanges();
+
+      const badge = fixture.nativeElement.querySelector('span.rounded-full');
+      expect(badge?.textContent?.trim()).toBe('Freigeschaltet');
+    });
+
+    it('should switch to all tab and show user data with role column', () => {
+      fixture.detectChanges();
+      const pendingReq = httpMock.expectOne((r) => r.url.includes('/admin/users/pending'));
+      pendingReq.flush([]);
+
+      component.switchTab('all');
+      const allReq = httpMock.expectOne((r) => r.url === '/api/admin/users');
+      allReq.flush([mockApprovedUser, mockPendingUser]);
+      fixture.detectChanges();
+
+      const rows = fixture.nativeElement.querySelectorAll('tbody tr');
+      expect(rows.length).toBe(2);
+
+      const allHeaders = fixture.nativeElement.querySelectorAll('th');
+      const headerTexts: string[] = [];
+      for (let i = 0; i < allHeaders.length; i++) {
+        headerTexts.push(allHeaders[i].textContent?.trim() || '');
+      }
+      expect(headerTexts).toContain('Rolle');
+    });
   });
 });