test: add tests for errorDetails with APIError and plain Error

frontend/src/container/GridCardLayout/GridCard/__tests__/errorDetails.test.ts

@@ -0,0 +1,65 @@
+import APIError from 'types/api/error';
+
+import { errorDetails } from '../utils';
+
+function makeAPIError(
+	message: string,
+	code = 'SOME_CODE',
+	errors: { message: string }[] = [],
+): APIError {
+	return new APIError({
+		httpStatusCode: 500,
+		error: { code, message, url: '', errors },
+	});
+}
+
+describe('errorDetails', () => {
+	describe('when passed an APIError', () => {
+		it('returns the error message', () => {
+			const error = makeAPIError('something went wrong');
+			expect(errorDetails(error)).toBe('something went wrong');
+		});
+
+		it('appends details when errors array is non-empty', () => {
+			const error = makeAPIError('query failed', 'QUERY_ERROR', [
+				{ message: 'field X is invalid' },
+				{ message: 'field Y is missing' },
+			]);
+			const result = errorDetails(error);
+			expect(result).toContain('query failed');
+			expect(result).toContain('field X is invalid');
+			expect(result).toContain('field Y is missing');
+		});
+
+		it('does not append details when errors array is empty', () => {
+			const error = makeAPIError('simple error', 'CODE', []);
+			const result = errorDetails(error);
+			expect(result).toBe('simple error');
+			expect(result).not.toContain('Details');
+		});
+	});
+
+	describe('when passed a plain Error (not an APIError)', () => {
+		it('does not throw', () => {
+			const error = new Error('timeout exceeded');
+			expect(() => errorDetails(error)).not.toThrow();
+		});
+
+		it('returns the plain error message', () => {
+			const error = new Error('timeout exceeded');
+			expect(errorDetails(error)).toBe('timeout exceeded');
+		});
+
+		it('returns fallback when plain Error has no message', () => {
+			const error = new Error('');
+			expect(errorDetails(error)).toBe('Unknown error occurred');
+		});
+	});
+
+	describe('fallback behaviour', () => {
+		it('returns "Unknown error occurred" when message is undefined', () => {
+			const error = makeAPIError('');
+			expect(errorDetails(error)).toBe('Unknown error occurred');
+		});
+	});
+});

frontend/src/container/GridCardLayout/GridCard/utils.ts

@@ -249,13 +249,14 @@ export const handleGraphClick = async ({
 	}
 };
 
-export const errorDetails = (error: APIError): string => {
-	const { message, errors } = error.getErrorDetails()?.error || {};
+export const errorDetails = (error: APIError | Error): string => {
+	const { message, errors } =
+		(error instanceof APIError ? error.getErrorDetails()?.error : null) || {};
 
 	const details =
-		errors?.length > 0
+		errors && errors.length > 0
 			? `\n\nDetails: ${errors.map((e) => e.message).join('\n')}`
 			: '';
-	const errorDetails = `${message} ${details}`;
-	return errorDetails || 'Unknown error occurred';
+	const errorDetails = `${message ?? error.message} ${details}`;
+	return errorDetails.trim() || 'Unknown error occurred';
 };