add a test target in the magefile

Author: David Bariod

.travis.yml

@@ -11,7 +11,4 @@ install:
 script:
   - go run mage.go -v crossBuild
   - go run mage.go lint
-  - export GOMAXPROCS=4
-  - export GORACE=halt_on_error=1
-  - go test -race -v ./...
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then go test -race -v -tags appengine ./... ; fi
+  - go run mage.go test

magefile.go

@@ -12,7 +12,7 @@ import (
 	"github.com/magefile/mage/sh"
 )
 
-// GenBuildMatrix regenerates the build matrix from the current version of the go compiler
+// getBuildMatrix returns the build matrix from the current version of the go compiler
 func getBuildMatrix() (map[string][]string, error) {
 	jsonData, err := sh.Output("go", "tool", "dist", "list", "-json")
 	if err != nil {
@@ -69,3 +69,9 @@ func Lint() error {
 
 	return sh.Run(path.Join(gopath, "bin", "golangci-lint"), "run", "./...")
 }
+
+// Run the test suite
+func Test() error {
+	return sh.RunWith(map[string]string{"GORACE": "halt_on_error=1"},
+		"go", "test", "-race", "-v", "./...")
+}