Update e2e test for image pull to check stdout

Also add TEST_DEBUG env variable for debugging E2E tests.
And change icmd environment helpers to fit the CmdOp interface os they
can be passed to 'icmd.RunCmd()'

Signed-off-by: Daniel Nephin <dnephin@docker.com>
(cherry picked from commit b11c11ea74)
Signed-off-by: Eli Uriegas <eli.uriegas@docker.com>

components/cli/scripts/test/e2e/run

@@ -80,6 +80,9 @@ case "$cmd" in
         cleanup "$unique_id" "$compose_env_file"
         exit $testexit
         ;;
+    shell)
+        $SHELL
+        ;;
     *)
         echo "Unknown command: $cmd"
         echo "Usage: "

components/cli/scripts/test/e2e/wrapper

@@ -32,13 +32,21 @@ docker run --rm \
 
 engine_host=$(run_in_env setup)
 testexit=0
+
+
+test_cmd="test"
+if [[ -n "${TEST_DEBUG-}" ]]; then
+    test_cmd="shell"
+fi
+
 docker run -i --rm \
     -v "$PWD:/go/src/github.com/docker/cli" \
     -v "$PWD/e2e/testdata/notary/root-ca.cert:/usr/local/share/ca-certificates/notary.cert" \
     --network "${unique_id}_default" \
     -e TESTFLAGS \
+    -e ENGINE_HOST="$engine_host" \
     "$dev_image" \
-    ./scripts/test/e2e/run test "$engine_host" || testexit="$?"
+    ./scripts/test/e2e/run "$test_cmd" "$engine_host" || testexit="$?"
 
 run_in_env cleanup
 exit "$testexit"