Increase unit test coverage of api/user.go (#4541)

* Add test to CheckUserDomain

* Add unit test to IsUsernameTaken

api/user_test.go

@@ -80,6 +80,51 @@ func TestCreateUser(t *testing.T) {
 	}
 }
 
+func TestCheckUserDomain(t *testing.T) {
+	th := Setup().InitBasic()
+	user := th.BasicUser
+
+	cases := []struct {
+		domains string
+		matched bool
+	}{
+		{"simulator.amazonses.com", true},
+		{"gmail.com", false},
+		{"", true},
+		{"gmail.com simulator.amazonses.com", true},
+	}
+	for _, c := range cases {
+		matched := CheckUserDomain(user, c.domains)
+		if matched != c.matched {
+			if c.matched {
+				t.Logf("'%v' should have matched '%v'", user.Email, c.domains)
+			} else {
+				t.Logf("'%v' should not have matched '%v'", user.Email, c.domains)
+			}
+			t.FailNow()
+		}
+	}
+}
+
+func TestIsUsernameTaken(t *testing.T) {
+	th := Setup().InitBasic()
+	user := th.BasicUser
+	taken := IsUsernameTaken(user.Username)
+
+	if !taken {
+		t.Logf("the username '%v' should be taken", user.Username)
+		t.FailNow()
+	}
+
+	newUsername := "randomUsername"
+	taken = IsUsernameTaken(newUsername)
+
+	if taken {
+		t.Logf("the username '%v' should not be taken", newUsername)
+		t.FailNow()
+	}
+}
+
 func TestLogin(t *testing.T) {
 	th := Setup()
 	Client := th.CreateClient()