diff --git a/test/lineCounter.js b/test/lineCounter.js
new file mode 100644
index 00000000000..5d2e59a26ff
--- /dev/null
+++ b/test/lineCounter.js
@@ -0,0 +1,18 @@
+const fs = require('fs');
+const assert = require('assert');
+const lineCounter = require('../src/utils/lineCounter');
+
+describe('line counter', () => {
+  it('counts number of lines of a string', () => {
+    const input = ` line 1
+      line 2
+      line 3`;
+
+    assert(lineCounter(input) === 3);
+  });
+
+  it('counts number of lines of a file from disk', () => {
+    const input = fs.readFileSync('./test/lineCounter.js').toString();
+    assert(lineCounter(input) === 19);
+  });
+});