started tests for ssh; added cover tool

Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>

Dockerfile

@@ -3,6 +3,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends openssh-client
 RUN go get github.com/mitchellh/gox
 RUN go get github.com/aktau/github-release
 RUN go get github.com/tools/godep
+RUN go get code.google.com/p/go.tools/cmd/cover
 ENV GOPATH /go/src/github.com/docker/machine/Godeps/_workspace:/go
 ENV MACHINE_BINARY /go/src/github.com/docker/machine/docker-machine
 WORKDIR /go/src/github.com/docker/machine

ssh/ssh_test.go

@@ -0,0 +1,28 @@
+package ssh
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestGenerateSSHKey(t *testing.T) {
+	tmpDir, err := ioutil.TempDir("", "machine-test-")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	filename := filepath.Join(tmpDir, "sshkey")
+
+	if err := GenerateSSHKey(filename); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err := os.Stat(filename); err != nil {
+		t.Fatalf("expected ssh key at %s", filename)
+	}
+
+	// cleanup
+	_ = os.RemoveAll(tmpDir)
+}