Add tests

src/spawn.spec.ts

@@ -1,34 +1,52 @@
-import { getSpawnOpts } from './spawn';
+import { getSpawnOpts, spawn } from './spawn';
 
 const baseProcess = {
     platform: 'win32' as const,
     cwd: () => '',
     env: {},
 };
 
-it('sets detached mode to false for Windows platform', () => {
-    expect(getSpawnOpts({ process: baseProcess }).detached).toBe(false);
-});
+describe('spawn()', () => {
+    it('spawns the given command', async () => {
+        const fakeSpawn = jest.fn();
+        spawn('echo banana', {}, fakeSpawn, baseProcess);
+        expect(fakeSpawn).toHaveBeenCalled();
+        expect(fakeSpawn.mock.calls[0][1].join(' ')).toContain('echo banana');
+    });
 
-it('sets stdio to inherit when raw', () => {
-    expect(getSpawnOpts({ raw: true }).stdio).toBe('inherit');
+    it('returns spawned process', async () => {
+        const childProcess = {};
+        const fakeSpawn = jest.fn().mockReturnValue(childProcess);
+        const child = spawn('echo banana', {}, fakeSpawn, baseProcess);
+        expect(child).toBe(childProcess);
+    });
 });
 
-it('merges FORCE_COLOR into env vars if color supported', () => {
-    const process = { ...baseProcess, env: { foo: 'bar' } };
-    expect(getSpawnOpts({ process, colorSupport: false }).env).toEqual(process.env);
-    expect(getSpawnOpts({ process, colorSupport: { level: 1 } }).env).toEqual({
-        FORCE_COLOR: '1',
-        foo: 'bar',
+describe('getSpawnOpts()', () => {
+    it('sets detached mode to false for Windows platform', () => {
+        expect(getSpawnOpts({ process: baseProcess }).detached).toBe(false);
     });
-});
 
-it('sets default cwd to process.cwd()', () => {
-    const process = { ...baseProcess, cwd: () => 'process-cwd' };
-    expect(getSpawnOpts({ process }).cwd).toBe('process-cwd');
-});
+    it('sets stdio to inherit when raw', () => {
+        expect(getSpawnOpts({ raw: true }).stdio).toBe('inherit');
+    });
 
-it('overrides default cwd', () => {
-    const cwd = 'foobar';
-    expect(getSpawnOpts({ cwd }).cwd).toBe(cwd);
+    it('merges FORCE_COLOR into env vars if color supported', () => {
+        const process = { ...baseProcess, env: { foo: 'bar' } };
+        expect(getSpawnOpts({ process, colorSupport: false }).env).toEqual(process.env);
+        expect(getSpawnOpts({ process, colorSupport: { level: 1 } }).env).toEqual({
+            FORCE_COLOR: '1',
+            foo: 'bar',
+        });
+    });
+
+    it('sets default cwd to process.cwd()', () => {
+        const process = { ...baseProcess, cwd: () => 'process-cwd' };
+        expect(getSpawnOpts({ process }).cwd).toBe('process-cwd');
+    });
+
+    it('overrides default cwd', () => {
+        const cwd = 'foobar';
+        expect(getSpawnOpts({ cwd }).cwd).toBe(cwd);
+    });
 });

src/spawn.ts

@@ -5,15 +5,21 @@ import supportsColor from 'supports-color';
  * Spawns a command using `cmd.exe` on Windows, or `/bin/sh` elsewhere.
  */
 // Implementation based off of https://github.com/mmalecki/spawn-command/blob/v0.0.2-1/lib/spawn-command.js
-export function spawn(command: string, options: SpawnOptions): ChildProcess {
+export function spawn(
+    command: string,
+    options: SpawnOptions,
+    // For testing
+    spawn: (command: string, args: string[], options: SpawnOptions) => ChildProcess = baseSpawn,
+    process: Pick<NodeJS.Process, 'platform'> = global.process,
+): ChildProcess {
     let file = '/bin/sh';
     let args = ['-c', command];
     if (process.platform === 'win32') {
         file = 'cmd.exe';
         args = ['/s', '/c', `"${command}"`];
         options.windowsVerbatimArguments = true;
     }
-    return baseSpawn(file, args, options);
+    return spawn(file, args, options);
 }
 
 export const getSpawnOpts = ({