Index: translate/storage/test_base.py
===================================================================
--- translate/storage/test_base.py	(revision 7770)
+++ translate/storage/test_base.py	(working copy)
@@ -126,6 +126,32 @@
         actual_notes = unit.getnotes()
         assert actual_notes == expected_notes
 
+    def test_prev_source(self):
+        unit = self.UnitClass("Test")
+        assert not unit.prev_source
+
+        unit.setprev_source("Tested")
+        assert unit.prev_source == "Tested"
+
+        unit.setprev_source("")
+        assert not unit.prev_source
+
+    def test_prev_context(self):
+        unit = self.UnitClass("Test ")
+        assert not unit.prev_context
+
+        unit.setprev_context("Tested Context")
+        assert unit.prev_context == "Tested Context"
+
+        unit.setprev_context("")
+        assert not unit.prev_context
+
+    def test_set_as_previous(self):
+        unit = self.UnitClass("Test")
+        unit.set_as_previous()
+        assert unit.prev_source == "Test"
+
+
 class TestTranslationStore:
     """Tests a TranslationStore.
     Derived classes can reuse these tests by pointing StoreClass to a derived Store"""