Try inline

test.mjs

@@ -1,23 +1,47 @@
-import { exec } from 'child_process';
-import fs from 'fs';
+import { spawnSync } from 'child_process';
 import assert from 'assert';
-import * as util from 'util';
-const execAsync = util.promisify(exec);
 
 async function main() {
-    const hash = 'e250bec';
-    const snapshotPath = `${hash}.snapshot`;
-    const { stdout, stderr } = await execAsync(
-        `git show ${hash} | node ./build/index.mjs --color`
+    const input = `
+commit e250bec66b6c39d4c2f9e0e52a18245f16a7195a
+Author: Shrey Banga <banga.shrey@gmail.com>
+Date:   Fri Dec 29 11:14:25 2023 -0500
+
+    Exclude lockfiles from diffs
+
+diff --git a/.gitattributes b/.gitattributes
+new file mode 100644
+index 0000000..c72d334
+--- /dev/null
++++ b/.gitattributes
+@@ -0,0 +1,3 @@
++# exclude lock files from git diff
++package-lock.json -diff
++yarn.lock -diff
+`;
+    const expected = `
+commit e250bec66b6c39d4c2f9e0e52a18245f16a7195a                                                                                                                                       
+Author: Shrey Banga <banga.shrey@gmail.com>                                                                                                                                           
+Date:   Fri Dec 29 11:14:25 2023 -0500                                                                                                                                                
+                                                                                                                                                                                      
+    Exclude lockfiles from diffs                                                                                                                                                      
+                                                                                                                                                                                      
+──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
+ ■■ .gitattributes                                                                                                                                                                    
+──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
+@@ -0,0 +1,3 @@                                                                                                                                                                       
+                                                                                               1  + # exclude lock files from git diff                                                
+                                                                                               2  + package-lock.json -diff                                                           
+                                                                                               3  + yarn.lock -diff                                                                   
+                                                                                               4                                                                                      
+`;
+    const { stdout, stderr } = spawnSync(
+        'node',
+        ['./build/index.mjs', '--color'],
+        { input, encoding: 'utf-8' }
     );
     console.log({ stdout, stderr });
-    if (fs.existsSync(snapshotPath)) {
-        const expected = fs.readFileSync(snapshotPath, 'utf-8');
-        assert.equal(stdout, expected);
-    } else {
-        fs.writeFileSync(snapshotPath, stdout);
-        console.log(`Wrote snapshot to ${snapshotPath}`);
-    }
+    assert.equal(stdout, expected);
 }
 
 main();