refactor: Clean up utility functions

test/unit/util/StreamUtil.test.ts

@@ -0,0 +1,43 @@
+import { PassThrough } from 'stream';
+import streamifyArray from 'streamify-array';
+import { pipeSafely, readableToString } from '../../../src/util/StreamUtil';
+
+describe('StreamUtil', (): void => {
+  describe('#readableToString', (): void => {
+    it('concatenates all elements of a Readable.', async(): Promise<void> => {
+      const stream = streamifyArray([ 'a', 'b', 'c' ]);
+      await expect(readableToString(stream)).resolves.toEqual('abc');
+    });
+  });
+
+  describe('#pipeSafely', (): void => {
+    it('pipes data from one stream to the other.', async(): Promise<void> => {
+      const input = streamifyArray([ 'data' ]);
+      const output = new PassThrough();
+      const piped = pipeSafely(input, output);
+      await expect(readableToString(piped)).resolves.toEqual('data');
+    });
+
+    it('pipes errors from one stream to the other.', async(): Promise<void> => {
+      const input = new PassThrough();
+      input.read = (): any => {
+        input.emit('error', new Error('error'));
+        return null;
+      };
+      const output = new PassThrough();
+      const piped = pipeSafely(input, output);
+      await expect(readableToString(piped)).rejects.toThrow(new Error('error'));
+    });
+
+    it('supports mapping errors to something else.', async(): Promise<void> => {
+      const input = streamifyArray([ 'data' ]);
+      input.read = (): any => {
+        input.emit('error', new Error('error'));
+        return null;
+      };
+      const output = new PassThrough();
+      const piped = pipeSafely(input, output, (): any => new Error('other error'));
+      await expect(readableToString(piped)).rejects.toThrow(new Error('other error'));
+    });
+  });
+});