add makefile with coverage (kubernetes-sigs#41)

* add makefile with coverage

* fix syntax, go get gocovmerge

.gitignore

@@ -37,3 +37,6 @@ Session.vim
 cscope.*
 
 /bazel-*
+
+# coverage output
+cover.out

Makefile

@@ -12,7 +12,24 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# cover-html creates coverage report for whole project excluding vendor and opens result in the default browser
+.PHONY: cover cover-html
+
+cover:
+	go get github.com/wadey/gocovmerge
+	$(eval PKGS := $(shell go list ./... | grep -v /vendor/))
+	$(eval PKGS_DELIM := $(shell echo $(PKGS) | sed -e 's/ /,/g'))
+	go list -f '{{if or (len .TestGoFiles) (len .XTestGoFiles)}}go test -test.v -test.timeout=120s -covermode=count -coverprofile={{.Name}}_{{len .Imports}}_{{len .Deps}}.coverprofile -coverpkg $(PKGS_DELIM) {{.ImportPath}}{{end}}' $(PKGS) | xargs -0 sh -c 
+	gocovmerge `ls *.coverprofile` > cover.out
+	rm *.coverprofile
+
+cover-html: cover
+	go tool cover -html cover.out
+
+
 # The verify target runs tasks similar to the CI tasks, but without code coverage
+.PHONY: verify
+
 verify:
 	vendor/github.com/kubernetes/repo-infra/verify/verify-boilerplate.sh --rootdir=${CURDIR}
 	vendor/github.com/kubernetes/repo-infra/verify/verify-go-src.sh -v --rootdir ${CURDIR}