diff --git a/package.json b/package.json
index eb3c9135..9a1dcf0c 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
     "mkdirp": "^0.5.1",
     "nock": "^2.5.0",
     "nyc": "^2.3.0",
+    "proxyquire": "^1.5.0",
     "rimraf": "^2.4.0",
     "semver": "^4.3.6",
     "standard": "^4.2.1",
diff --git a/test/specs/commits.js b/test/specs/commits.js
new file mode 100644
index 00000000..1b6a1100
--- /dev/null
+++ b/test/specs/commits.js
@@ -0,0 +1,40 @@
+const test = require('tap').test
+const proxyquire = require('proxyquire')
+
+const rawCommits = [
+  'hash-one==SPLIT==commit-one==END==\n',
+  'hash-two==SPLIT==commit-two==END==\n'
+]
+const commits = proxyquire('../../dist/lib/commits.js', {
+  'child_process': {
+    exec: (command, cb) => {
+      cb(
+        null,
+        /\.\.HEAD/.test(command) ?
+          rawCommits[0] :
+          rawCommits.join()
+      )
+    },
+    '@noCallThru': true
+  }
+})
+
+test('commits since last release', (t) => {
+  t.test('get all commits', (t) => {
+    commits({lastRelease: {}}, (err, commits) => {
+      t.error(err)
+      t.is(commits.length, 2, 'all commits')
+      t.is(commits[0].hash, 'hash-one', 'parsed hash')
+      t.is(commits[1].message, 'commit-two', 'parsed message')
+    })
+  })
+
+  t.test('get commits since hash', (t) => {
+    commits({lastRelease: {gitHead: 'hash'}}, (err, commits) => {
+      t.error(err)
+      t.is(commits.length, 1, 'specified commits')
+      t.is(commits[0].hash, 'hash-one', 'parsed hash')
+      t.is(commits[0].message, 'commit-one', 'parsed message')
+    })
+  })
+})