Add containerized options for tests in Makefile

Add an option to run the `test-unit`, `test-style`, and `test`
steps from the `Makefile` insides of a docker container. Doing so
isolates this component of helm development from any other aspect of
your global go environment.

These commands all have the name `docker-*`. Long term, there may
be reproducibility benefits to running all of the Make steps in a
container by default, in which case `containerized-test-unit` could
become `test-unit`.

Makefile

 DOCKER_REGISTRY   ?= gcr.io
 IMAGE_PREFIX      ?= kubernetes-helm
+DEV_IMAGE         ?= golang:1.10
 SHORT_NAME        ?= tiller
 SHORT_NAME_RUDDER ?= rudder
 TARGETS           ?= darwin/amd64 linux/amd64 linux/386 linux/arm linux/arm64 linux/ppc64le linux/s390x windows/amd64
@@ -87,17 +88,39 @@ test: TESTFLAGS += -race -v
 test: test-style
 test: test-unit
 
+.PHONY: docker-test
+docker-test: docker-binary
+docker-test: TESTFLAGS += -race -v
+docker-test: docker-test-style
+docker-test: docker-test-unit
+
 .PHONY: test-unit
 test-unit:
 	@echo
 	@echo "==> Running unit tests <=="
 	HELM_HOME=/no/such/dir $(GO) test $(GOFLAGS) -run $(TESTS) $(PKG) $(TESTFLAGS)
 
+.PHONY: docker-test-unit
+docker-test-unit: check-docker
+	docker run \
+		-v $(shell pwd):/go/src/k8s.io/helm \
+		-w /go/src/k8s.io/helm \
+		$(DEV_IMAGE) \
+		bash -c "HELM_HOME=/no/such/dir go test $(GOFLAGS) -run $(TESTS) $(PKG) $(TESTFLAGS)"
+
 .PHONY: test-style
 test-style:
 	@scripts/validate-go.sh
 	@scripts/validate-license.sh
 
+.PHONY: docker-test-style
+docker-test-style: check-docker
+	docker run \
+		-v $(CURDIR):/go/src/k8s.io/helm \
+		-w /go/src/k8s.io/helm \
+		$(DEV_IMAGE) \
+		bash -c "scripts/validate-go.sh && scripts/validate-license.sh"
+
 .PHONY: protoc
 protoc:
 	$(MAKE) -C _proto/ all

docs/developers.md

@@ -27,7 +27,8 @@ This will build both Helm and Tiller. `make bootstrap` will attempt to
 install certain tools if they are missing.
 
 To run all the tests (without running the tests for `vendor/`), run
-`make test`.
+`make test`. To run all tests in a containerized environment, run `make
+docker-test`.
 
 To run Helm and Tiller locally, you can run `bin/helm` or `bin/tiller`.
 
@@ -209,6 +210,9 @@ We follow the Go coding style standards very closely. Typically, running
 
 We also typically follow the conventions recommended by `go lint` and
 `gometalinter`. Run `make test-style` to test the style conformance.
+If you do not want to install all the linters from `gometalinter` into your
+global Go environment, you can run `make docker-test-style` which will
+run the same tests, but isolated within a docker container.
 
 Read more: