Add areErrorsEqual equality tester

- This was done to make sure `toHaveBeenCalledWith` will fail if we pass in the wrong Error constructor. For example the assertion will now fail if we pass in an `Error` instead of a `TypeError`.

Author: aryaemami59

packages/toolkit/vitest.setup.ts

@@ -5,6 +5,46 @@ vi.stubGlobal('fetch', nodeFetch)
 vi.stubGlobal('Request', Request)
 vi.stubGlobal('Headers', Headers)
 
+/**
+ * Compares two values to determine if they are instances of {@linkcode Error}
+ * and have the same {@linkcode Error.name | name}
+ * and {@linkcode Error.message | message} properties.
+ *
+ * @param actualError - The actual error to compare.
+ * @param expectedError - The expected error to compare against.
+ * @returns `true` if both values are instances of {@linkcode Error} and have the same {@linkcode Error.name | name} and {@linkcode Error.message | message}.
+ *
+ * @example
+ * <caption>#### __Pass: The actual error is an instance of `TypeError` with the same `message` ✔️__</caption>
+ *
+ * ```ts
+ * expect(consoleErrorSpy).toHaveBeenLastCalledWith(
+ *   TypeError('endpointDefinition.queryFn is not a function'),
+ * )
+ * ```
+ *
+ * @example
+ * <caption>#### __Fail: The actual error is a `TypeError`, which is more specific than the expected generic `Error` ❌__</caption>
+ *
+ * ```ts
+ * expect(consoleErrorSpy).toHaveBeenLastCalledWith(
+ *   Error('endpointDefinition.queryFn is not a function'),
+ * )
+ * ```
+ *
+ * @internal
+ */
+const areErrorsEqual = (actualError: unknown, expectedError: unknown) => {
+  if (actualError instanceof Error && expectedError instanceof Error) {
+    return (
+      actualError.name === expectedError.name &&
+      actualError.message === expectedError.message
+    )
+  }
+}
+
+expect.addEqualityTesters([areErrorsEqual])
+
 beforeAll(() => {
   server.listen({ onUnhandledRequest: 'error' })
 })