feat: Create ErrorHandler to convert errors to Representations

test/unit/ldp/http/TextErrorHandler.test.ts

@@ -0,0 +1,60 @@
+import 'jest-rdf';
+import { DataFactory } from 'n3';
+import stringifyStream from 'stream-to-string';
+import { TextErrorHandler } from '../../../../src/ldp/http/TextErrorHandler';
+import { NotFoundHttpError } from '../../../../src/util/errors/NotFoundHttpError';
+import { HTTP, XSD } from '../../../../src/util/Vocabularies';
+import literal = DataFactory.literal;
+
+describe('A TextErrorHandler', (): void => {
+  // The error object can get modified by the handler
+  let error: Error;
+  let stack: string | undefined;
+  let handler: TextErrorHandler;
+
+  beforeEach(async(): Promise<void> => {
+    error = new NotFoundHttpError('not here');
+    ({ stack } = error);
+
+    handler = new TextErrorHandler(true);
+  });
+
+  it('can handle everything.', async(): Promise<void> => {
+    await expect(handler.canHandle({} as any)).resolves.toBeUndefined();
+  });
+
+  it('creates a text representation of the error.', async(): Promise<void> => {
+    const prom = handler.handle({ error } as any);
+    await expect(prom).resolves.toBeDefined();
+    const result = await prom;
+    expect(result.statusCode).toBe(404);
+    expect(result.metadata?.get(HTTP.terms.statusCodeNumber)).toEqualRdfTerm(literal(404, XSD.terms.integer));
+    expect(result.metadata?.contentType).toBe('text/plain');
+    const text = await stringifyStream(result.data!);
+    expect(text).toBe(`${stack}\n`);
+  });
+
+  it('concatenates name and message if there is no stack.', async(): Promise<void> => {
+    delete error.stack;
+    const prom = handler.handle({ error } as any);
+    await expect(prom).resolves.toBeDefined();
+    const result = await prom;
+    expect(result.statusCode).toBe(404);
+    expect(result.metadata?.get(HTTP.terms.statusCodeNumber)).toEqualRdfTerm(literal(404, XSD.terms.integer));
+    expect(result.metadata?.contentType).toBe('text/plain');
+    const text = await stringifyStream(result.data!);
+    expect(text).toBe(`NotFoundHttpError: not here\n`);
+  });
+
+  it('hides the stack trace if the option is disabled.', async(): Promise<void> => {
+    handler = new TextErrorHandler();
+    const prom = handler.handle({ error } as any);
+    await expect(prom).resolves.toBeDefined();
+    const result = await prom;
+    expect(result.statusCode).toBe(404);
+    expect(result.metadata?.get(HTTP.terms.statusCodeNumber)).toEqualRdfTerm(literal(404, XSD.terms.integer));
+    expect(result.metadata?.contentType).toBe('text/plain');
+    const text = await stringifyStream(result.data!);
+    expect(text).toBe(`NotFoundHttpError: not here\n`);
+  });
+});