diff --git a/.travis.yml b/.travis.yml
index 2b4907e..6af9fb4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,12 +1,12 @@
 language: go
 go:
-- 1.6.2
+  - 1.6.2
 before_install:
-  sudo pip install codecov
+  - sudo pip install codecov
 install:
-- make setup
+  - make setup
 script:
-- make cover
+  - make cover
 after_success:
-  codecov
+  - codecov
 
diff --git a/appstore/validator_test.go b/appstore/validator_test.go
index 3afc638..e97aad4 100644
--- a/appstore/validator_test.go
+++ b/appstore/validator_test.go
@@ -64,7 +64,7 @@ func TestHandleError(t *testing.T) {
 	}
 
 	// status unknown
-	expected = errors.New("An unknown error ocurred")
+	expected = errors.New("An unknown error occurred")
 	actual = HandleError(100)
 	if !reflect.DeepEqual(actual, expected) {
 		t.Errorf("got %v\nwant %v", actual, expected)
diff --git a/playstore/validator_test.go b/playstore/validator_test.go
index 94341b9..0a04a1d 100644
--- a/playstore/validator_test.go
+++ b/playstore/validator_test.go
@@ -1,7 +1,7 @@
 package playstore
 
 import (
-	"encoding/json"
+	"encoding/base64"
 	"errors"
 	"reflect"
 	"testing"
@@ -10,28 +10,31 @@ import (
 	"golang.org/x/oauth2"
 )
 
-type testSignature struct {
-	PrivateKeyID string `json:"private_key_id"`
-	PrivateKey   string `json:"private_key"`
-	ClientEmail  string `json:"client_email"`
-	ClientID     string `json:"client_id"`
-	Type         string `json:"type"`
-}
+var base64JsonKey = "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"
 
-var testJSON = testSignature{
-	PrivateKeyID: "dummyKeyID",
-	PrivateKey:   "-----BEGIN PRIVATE KEY-----\nMIIBOQIBAAJBANXOa7wgs5KHMEVJmVo2eoRxEgeqiYF2oABPGYrebU+cQiE7Mwdy\nxv153DHME+9L9QzAj+fR4y5Rwva/fAsGAssCAwEAAQJATQwrFMtwCtC+22kvYywY\nsJuSlMKm9MmL1TCsErgfCj2rksRK1U+/ZY709tE3XJVYlZalWCeVhHTjs5p0pnk6\nYQIhAOw0FksytfIfpdfcREbful+LhFp1um5WjcVf7kQ73JDxAiEA57nJkG9pwnUd\nBCyIcElTVIAKU0+iFpd1208OnGxyT3sCIGaEBNkGXWmEytnxQ8DvAVjOmNcaGZwh\n/M4ZYLREtupBAiAsrpFkTWdqPKTcsi2Y4Tq1N39GMzvA+XGbWTIrDWo5UwIgHhp9\nEOnHuUuPCjpLfYM2vSFiYzaj8UJCImjkMtDwzbA=\n-----END PRIVATE KEY-----\n",
-	ClientEmail:  "dummyEmail",
-	ClientID:     "dummyClientID",
-	Type:         "service_account",
+var base64dummyKey = "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"
+
+var jsonKey []byte
+var dummyKey []byte
+
+func init() {
+	f, err := base64.StdEncoding.DecodeString(base64JsonKey)
+	if err != nil {
+		panic(err)
+	}
+	jsonKey = f
+	d, err := base64.StdEncoding.DecodeString(base64dummyKey)
+	if err != nil {
+		panic(err)
+	}
+	dummyKey = d
 }
 
 func TestNew(t *testing.T) {
 	// Exception scenario
-	jsonKey, _ := json.Marshal(testJSON)
-	expected := "oauth2: cannot fetch token: 400 Bad Request\nResponse: {\n  \"error\" : \"invalid_grant\"\n}"
+	expected := "oauth2: cannot fetch token: 401 Unauthorized\nResponse: {\n  \"error\" : \"invalid_client\",\n  \"error_description\" : \"The OAuth client was invalid.\"\n}"
 
-	actual, _ := New(jsonKey)
+	actual, _ := New(dummyKey)
 	val := actual.httpClient.Transport.(*oauth2.Transport)
 	token, err := val.Source.Token()
 	if token != nil {
@@ -42,6 +45,12 @@ func TestNew(t *testing.T) {
 	}
 
 	// TODO Normal scenario
+	actual, _ = New(jsonKey)
+	val = actual.httpClient.Transport.(*oauth2.Transport)
+	token, err = val.Source.Token()
+	if err != nil {
+		t.Errorf("got %#v", err)
+	}
 }
 
 func TestSetTimeout(t *testing.T) {
@@ -55,9 +64,7 @@ func TestSetTimeout(t *testing.T) {
 
 func TestVerifySubscription(t *testing.T) {
 	// Exception scenario
-	jsonKey, _ := json.Marshal(testJSON)
-
-	expected := "Get https://www.googleapis.com/androidpublisher/v2/applications/package/purchases/subscriptions/subscriptionID/tokens/purchaseToken?alt=json: oauth2: cannot fetch token: 400 Bad Request\nResponse: {\n  \"error\" : \"invalid_grant\"\n}"
+	expected := "googleapi: Error 404: No application was found for the given package name., applicationNotFound"
 
 	client, _ := New(jsonKey)
 	_, err := client.VerifySubscription("package", "subscriptionID", "purchaseToken")
@@ -81,9 +88,7 @@ func TestVerifySubscriptionAndroidPublisherError(t *testing.T) {
 
 func TestVerifyProduct(t *testing.T) {
 	// Exception scenario
-	jsonKey, _ := json.Marshal(testJSON)
-
-	expected := "Get https://www.googleapis.com/androidpublisher/v2/applications/package/purchases/products/productID/tokens/purchaseToken?alt=json: oauth2: cannot fetch token: 400 Bad Request\nResponse: {\n  \"error\" : \"invalid_grant\"\n}"
+	expected := "googleapi: Error 404: No application was found for the given package name., applicationNotFound"
 
 	client, _ := New(jsonKey)
 	_, err := client.VerifyProduct("package", "productID", "purchaseToken")
@@ -115,9 +120,8 @@ func TestCancelSubscription(t *testing.T) {
 		t.Errorf("got %v\nwant %v", actual, expected)
 	}
 
-	jsonKey, _ := json.Marshal(testJSON)
 	client, _ = New(jsonKey)
-	expectedStr := "Post https://www.googleapis.com/androidpublisher/v2/applications/package/purchases/subscriptions/productID/tokens/purchaseToken:cancel?alt=json: oauth2: cannot fetch token: 400 Bad Request\nResponse: {\n  \"error\" : \"invalid_grant\"\n}"
+	expectedStr := "googleapi: Error 404: No application was found for the given package name., applicationNotFound"
 	actual = client.CancelSubscription("package", "productID", "purchaseToken")
 
 	if actual.Error() != expectedStr {
@@ -137,9 +141,8 @@ func TestRefundSubscription(t *testing.T) {
 		t.Errorf("got %v\nwant %v", actual, expected)
 	}
 
-	jsonKey, _ := json.Marshal(testJSON)
 	client, _ = New(jsonKey)
-	expectedStr := "Post https://www.googleapis.com/androidpublisher/v2/applications/package/purchases/subscriptions/productID/tokens/purchaseToken:refund?alt=json: oauth2: cannot fetch token: 400 Bad Request\nResponse: {\n  \"error\" : \"invalid_grant\"\n}"
+	expectedStr := "googleapi: Error 404: No application was found for the given package name., applicationNotFound"
 	actual = client.RefundSubscription("package", "productID", "purchaseToken")
 
 	if actual.Error() != expectedStr {
@@ -159,9 +162,8 @@ func TestRevokeSubscription(t *testing.T) {
 		t.Errorf("got %v\nwant %v", actual, expected)
 	}
 
-	jsonKey, _ := json.Marshal(testJSON)
 	client, _ = New(jsonKey)
-	expectedStr := "Post https://www.googleapis.com/androidpublisher/v2/applications/package/purchases/subscriptions/productID/tokens/purchaseToken:revoke?alt=json: oauth2: cannot fetch token: 400 Bad Request\nResponse: {\n  \"error\" : \"invalid_grant\"\n}"
+	expectedStr := "googleapi: Error 404: No application was found for the given package name., applicationNotFound"
 	actual = client.RevokeSubscription("package", "productID", "purchaseToken")
 
 	if actual.Error() != expectedStr {