Stringify arg provided to assertNever error message (#42)

Author: jossmac

src/assertions.test.ts

@@ -56,7 +56,7 @@ describe('assertions', () => {
         // @ts-expect-error: for testing
         assertNever(value);
       } catch (error) {
-        expect(getErrorMessage(error)).toBe(`Unexpected call to assertNever: '${value}'`);
+        expect(getErrorMessage(error)).toBe(`Expected never to be called, but received: ${value}`);
       }
     });
   });

src/assertions.ts

@@ -19,8 +19,8 @@ export function assert(condition: boolean, message = 'Assert failed'): asserts c
  *
  * @throws always
  */
-export function assertNever(condition: never): never {
-  throw new Error(`Unexpected call to assertNever: '${condition}'`);
+export function assertNever(arg: never): never {
+  throw new Error('Expected never to be called, but received: ' + JSON.stringify(arg));
 }
 
 /**