diff --git a/cmd/kubeadm/app/util/tokens.go b/cmd/kubeadm/app/util/tokens.go
index 3be338470cd..34b6bbf407b 100644
--- a/cmd/kubeadm/app/util/tokens.go
+++ b/cmd/kubeadm/app/util/tokens.go
@@ -66,9 +66,8 @@ func UseGivenTokenIfValid(s *kubeadmapi.Secrets) (bool, error) {
 	}
 	fmt.Println("<util/tokens> validating provided token")
 	givenToken := strings.Split(strings.ToLower(s.GivenToken), ".")
-	// TODO(phase1+) print desired format
 	// TODO(phase1+) could also print more specific messages in each case
-	invalidErr := "<util/tokens> provided token is invalid - %s"
+	invalidErr := "<util/tokens> provided token does not match expected <6 characters>.<16 characters> format - %s"
 	if len(givenToken) != 2 {
 		return false, fmt.Errorf(invalidErr, "not in 2-part dot-separated format")
 	}
diff --git a/cmd/kubeadm/app/util/tokens_test.go b/cmd/kubeadm/app/util/tokens_test.go
new file mode 100644
index 00000000000..7a33cced6e0
--- /dev/null
+++ b/cmd/kubeadm/app/util/tokens_test.go
@@ -0,0 +1,85 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"bytes"
+	"testing"
+
+	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
+)
+
+func TestUsingEmptyTokenFails(t *testing.T) {
+	// Simulates what happens when you omit --token on the CLI
+	s := newSecretsWithToken("")
+
+	given, err := UseGivenTokenIfValid(s)
+	if err != nil {
+		t.Errorf("UseGivenTokenIfValid returned an error when the token was omitted: %v", err)
+	}
+	if given {
+		t.Error("UseGivenTokenIfValid returned given = true when the token was omitted; expected false")
+	}
+}
+
+func TestTokenValidationFailures(t *testing.T) {
+	invalidTokens := []string{
+		"1234567890123456789012",
+		"12345.1234567890123456",
+		".1234567890123456",
+		"123456.1234567890.123456",
+	}
+
+	for _, token := range invalidTokens {
+		s := newSecretsWithToken(token)
+		_, err := UseGivenTokenIfValid(s)
+
+		if err == nil {
+			t.Errorf("UseGivenTokenIfValid did not return an error for this invalid token: [%s]", token)
+		}
+	}
+}
+
+func TestValidTokenPopulatesSecrets(t *testing.T) {
+	s := newSecretsWithToken("123456.0123456789AbCdEf")
+	expectedToken := []byte("0123456789abcdef")
+	expectedTokenID := "123456"
+	expectedBearerToken := "0123456789abcdef"
+
+	given, err := UseGivenTokenIfValid(s)
+	if err != nil {
+		t.Errorf("UseGivenTokenIfValid gave an error for a valid token: %v", err)
+	}
+	if !given {
+		t.Error("UseGivenTokenIfValid returned given = false when given a valid token")
+	}
+	if s.TokenID != expectedTokenID {
+		t.Errorf("UseGivenTokenIfValid did not populate the TokenID correctly; expected [%s] but got [%s]", expectedTokenID, s.TokenID)
+	}
+	if s.BearerToken != expectedBearerToken {
+		t.Errorf("UseGivenTokenIfValid did not populate the BearerToken correctly; expected [%s] but got [%s]", expectedBearerToken, s.BearerToken)
+	}
+	if !bytes.Equal(s.Token, expectedToken) {
+		t.Errorf("UseGivenTokenIfValid did not populate the Token correctly; expected %v but got %v", expectedToken, s.Token)
+	}
+}
+
+func newSecretsWithToken(token string) *kubeadmapi.Secrets {
+	s := new(kubeadmapi.Secrets)
+	s.GivenToken = token
+	return s
+}