diff --git a/test/test_adjusters.py b/test/test_adjusters.py
index 4a6e283..f03b7d2 100644
--- a/test/test_adjusters.py
+++ b/test/test_adjusters.py
@@ -1,5 +1,6 @@
 """test_adjusters.py -- test pipeline Adjusters (eg TargetTimeAdjuster)"""
 import unittest
+import unittest.mock as mock
 import pipeline.adjusters as adjusters
 
 class TestAdjuster(unittest.TestCase):
@@ -15,3 +16,28 @@ class TestAdjuster(unittest.TestCase):
         adjuster = adjusters.Adjuster()
         self.assertEqual(adjuster.adjust(), [])
         self.assertEqual(adjuster.features, [])
+
+class TestTargetTimeAdjuster(unittest.TestCase):
+    """Test the TargetTimeAdjuster
+
+    TTA drops Features until the target time is reached (or within a margin)"""
+
+    def test_init(self):
+        """Test the TTA can be initialised"""
+        tta = adjusters.TargetTimeAdjuster()
+        self.assertEqual(tta.features, [])
+
+    def test_features_total_time(self):
+        """Test the TTA can calculate the total time of Features
+
+        Test:
+         - input duration floats: 1.0, 2.0, 3.0, 4.0 == 10.0
+        """
+        tta = adjusters.TargetTimeAdjuster()
+        features = []
+        for i in range(1, 5):
+            features.append(mock.Mock(duration=i*1.0))
+
+        self.assertEqual(tta._features_total_time(features), 10.0)
+        self.assertEqual(tta._features_total_time([]), 0.0)
+        self.assertIs(type(tta._features_total_time([])), float)