workdir integration test

integration_tests/dockerfiles/Dockerfile_test_workdir

@@ -1,10 +1,13 @@
 FROM gcr.io/google-appengine/debian9:latest
 COPY context/foo foo
 WORKDIR /test
-WORKDIR workdir
-COPY context/foo .
-RUN cp foo newfoo
+# Test that this will be appended on to the previous command, to create /test/workdir
+WORKDIR workdir 
+COPY context/foo ./currentfoo
+# Test that the RUN command will happen in the correct directory
+RUN cp currentfoo newfoo
 WORKDIR /new/dir
 ENV dir /another/new/dir
 WORKDIR $dir/newdir
+WORKDIR $dir/$doesntexist
 WORKDIR /