diff --git a/src/dialogs/certificate-import-dialog/useCertificateImportDialog.test.tsx b/src/dialogs/certificate-import-dialog/useCertificateImportDialog.test.tsx
index 0162520e..c3235bea 100644
--- a/src/dialogs/certificate-import-dialog/useCertificateImportDialog.test.tsx
+++ b/src/dialogs/certificate-import-dialog/useCertificateImportDialog.test.tsx
@@ -5,12 +5,14 @@ import { useCertificateImportDialog } from "./useCertificateImportDialog";
 
 import type { IProviderInfo, FortifyAPI } from "@peculiar/fortify-client-core";
 
+const mockAddToast = vi.fn();
+
 vi.mock("@peculiar/react-components", async () => {
   const actual = await vi.importActual("@peculiar/react-components");
   return {
     ...actual,
     useToast: () => ({
-      addToast: vi.fn(),
+      addToast: mockAddToast,
     }),
   };
 });
@@ -87,8 +89,7 @@ describe("useCertificateImportDialog", () => {
     });
 
     act(() => {
-      const DialogComponent = result.current.dialog();
-      DialogComponent && DialogComponent.props.onTextAreaChange(certificate);
+      result.current.dialog()?.props.onTextAreaChange(certificate);
     });
 
     await act(async () => {
@@ -133,4 +134,85 @@ describe("useCertificateImportDialog", () => {
   it("Should upload file certificate & call onSuccess (CSR)", async () => {
     await testFileUploadCertificate(certificateCSRPem, "csr");
   });
+
+  it("Should handle text area validation error", () => {
+    const { result } = renderHook(() =>
+      useCertificateImportDialog({
+        providers,
+        onSuccess: vi.fn(),
+        fortifyClient: mockFortifyClient as FortifyAPI,
+      })
+    );
+
+    act(() => {
+      result.current.open();
+    });
+
+    act(() => {
+      result.current.dialog()?.props.onTextAreaChange("certificate");
+    });
+
+    act(() => {
+      result.current.dialog()?.props.onTextAreaBlur();
+    });
+
+    expect(result.current.dialog()?.props.isTextAreaError).toBeTruthy();
+  });
+
+  it("Should handle file rejection correctly", () => {
+    const { result } = renderHook(() =>
+      useCertificateImportDialog({
+        providers,
+        onSuccess: vi.fn(),
+        fortifyClient: mockFortifyClient as FortifyAPI,
+      })
+    );
+
+    act(() => {
+      result.current.open();
+    });
+
+    const errorMessage = "Error message";
+    act(() => {
+      result.current.dialog()?.props.onDropRejected(errorMessage);
+    });
+
+    expect(mockAddToast).toHaveBeenCalledWith(
+      expect.objectContaining({
+        message: errorMessage,
+        variant: "wrong",
+      })
+    );
+  });
+
+  it("Should handle the error when uploading an invalid certificate", async () => {
+    const byteArray = new TextEncoder().encode("certificate");
+    const { result } = renderHook(() =>
+      useCertificateImportDialog({
+        providers,
+        onSuccess: vi.fn(),
+        fortifyClient: mockFortifyClient as FortifyAPI,
+      })
+    );
+
+    act(() => {
+      result.current.open();
+    });
+
+    await act(async () => {
+      const DialogComponent = result.current.dialog();
+      if (DialogComponent) {
+        DialogComponent.props.onDropAccepted(byteArray.buffer, "cer", "");
+        await DialogComponent.props.onImportButtonClick();
+      }
+    });
+
+    expect(mockAddToast).toHaveBeenCalledWith(
+      expect.objectContaining({
+        message:
+          "Certificate is invalid. Please check your data and try again.",
+        variant: "wrong",
+      })
+    );
+  });
 });