Add the long forgotten tests for test_usages.py

test/test_api/test_usages.py

@@ -0,0 +1,6 @@
+import jedi
+
+
+def test_import_usage():
+    s = jedi.Script("from .. import foo", line=1, column=18, path="foo.py")
+    assert [usage.line for usage in s.usages()] == [1]