test: write tests for ProcessRepository#createSpawnDuplexStream

server/src/repositories/process.repository.spec.ts

@@ -0,0 +1,85 @@
+import { ChildProcessWithoutNullStreams } from 'node:child_process';
+import { Readable, Writable } from 'node:stream';
+import { pipeline } from 'node:stream/promises';
+import { ProcessRepository } from 'src/repositories/process.repository';
+
+describe(ProcessRepository.name, () => {
+  let sut: ProcessRepository;
+  let sink: Writable;
+
+  beforeAll(() => {
+    sut = new ProcessRepository();
+  });
+
+  beforeEach(() => {
+    sink = new Writable({
+      write(_chunk, _encoding, callback) {
+        callback();
+      },
+
+      final(callback) {
+        callback();
+      },
+    });
+  });
+
+  describe('createSpawnDuplexStream', () => {
+    it('should work (drain to stdout)', async () => {
+      const process = sut.createSpawnDuplexStream('bash', ['-c', 'exit 0']);
+      await pipeline(process, sink);
+    });
+
+    it('should throw on non-zero exit code', async () => {
+      const process = sut.createSpawnDuplexStream('bash', ['-c', 'echo "error message" >&2; exit 1']);
+      await expect(pipeline(process, sink)).rejects.toThrowErrorMatchingInlineSnapshot(`
+        [Error: bash non-zero exit code (1)
+        error message
+        ]
+      `);
+    });
+
+    it('should accept stdin / output stdout', async () => {
+      async function* data() {
+        yield 'Hello, world!';
+      }
+
+      let output = '';
+      const sink = new Writable({
+        write(chunk, _encoding, callback) {
+          output += chunk;
+          callback();
+        },
+
+        final(callback) {
+          callback();
+        },
+      });
+
+      const echoProcess = sut.createSpawnDuplexStream('cat');
+      await pipeline(Readable.from(data()), echoProcess, sink);
+      expect(output).toBe('Hello, world!');
+    });
+
+    it('should drain stdin on process exit', async () => {
+      let resolve1: () => void;
+      let resolve2: () => void;
+      const promise1 = new Promise<void>((r) => (resolve1 = r));
+      const promise2 = new Promise<void>((r) => (resolve2 = r));
+
+      async function* data() {
+        yield 'Hello, world!';
+        await promise1;
+        await promise2;
+        yield 'Write after stdin close / process exit!';
+      }
+
+      const process = sut.createSpawnDuplexStream('bash', ['-c', 'exit 0']);
+
+      const realProcess = (process as never as { _process: ChildProcessWithoutNullStreams })._process;
+      realProcess.on('close', () => setImmediate(() => resolve1()));
+      realProcess.stdin.on('close', () => setImmediate(() => resolve2()));
+
+      await pipeline(Readable.from(data()), process);
+    });
+  });
+});