Add basic tests

pkg/github/client_test.go

@@ -0,0 +1,23 @@
+package github
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGithubTokenIsAbsent(t *testing.T) {
+	client, err := NewWithAuth("johndoe", "")
+	assert.Nil(t, client)
+	assert.Contains(t, err.Error(), "Github Token is required")
+}
+func TestGithubUsernameIsAbsent(t *testing.T) {
+	client, err := NewWithAuth("", "invalid")
+	assert.Nil(t, client)
+	assert.Contains(t, err.Error(), "Github username is required")
+}
+func TestGithubTokenValidity(t *testing.T) {
+	client, _ := NewWithAuth("johndoe", "invalid")
+	ok := client.IsTokenValid()
+	assert.False(t, ok)
+}