refactor: enhance NewClient to support environment variable fallback and add tests

dns_test.go

@@ -10,8 +10,74 @@ import (
 	"testing"
 )
 
+func TestNewClient_miabStyle(t *testing.T) {
+	t.Setenv("MIAB_HOST", "box.example.com")
+	t.Setenv("MIAB_USERNAME", "user@example.com")
+	t.Setenv("MIAB_PASSWORD", "secret")
+
+	c, err := NewClient("", "", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.host != "box.example.com" || c.username != "user@example.com" || c.password != "secret" {
+		t.Errorf("unexpected client fields: %+v", c)
+	}
+}
+
+func TestNewClient_mailinaboxStyle(t *testing.T) {
+	t.Setenv("MAILINABOX_BASE_URL", "https://box.example.com")
+	t.Setenv("MAILINABOX_EMAIL", "user@example.com")
+	t.Setenv("MAILINABOX_PASSWORD", "secret")
+
+	c, err := NewClient("", "", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.host != "box.example.com" || c.username != "user@example.com" || c.password != "secret" {
+		t.Errorf("unexpected client fields: %+v", c)
+	}
+}
+
+func TestNewClient_miabTakesPrecedence(t *testing.T) {
+	t.Setenv("MIAB_HOST", "miab.example.com")
+	t.Setenv("MIAB_USERNAME", "miab@example.com")
+	t.Setenv("MIAB_PASSWORD", "miabpass")
+	t.Setenv("MAILINABOX_BASE_URL", "https://other.example.com")
+	t.Setenv("MAILINABOX_EMAIL", "other@example.com")
+	t.Setenv("MAILINABOX_PASSWORD", "otherpass")
+
+	c, err := NewClient("", "", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.host != "miab.example.com" || c.username != "miab@example.com" || c.password != "miabpass" {
+		t.Errorf("MIAB_* vars should take precedence, got: %+v", c)
+	}
+}
+
+func TestNewClient_missingVars(t *testing.T) {
+	_, err := NewClient("", "", "")
+	if err == nil {
+		t.Fatal("expected error when no env vars set")
+	}
+}
+
+func TestNewClient_explicitParamsTakePrecedence(t *testing.T) {
+	t.Setenv("MIAB_HOST", "env.example.com")
+	t.Setenv("MIAB_USERNAME", "env@example.com")
+	t.Setenv("MIAB_PASSWORD", "envpass")
+
+	c, err := NewClient("explicit.example.com", "explicit@example.com", "explicitpass")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.host != "explicit.example.com" || c.username != "explicit@example.com" || c.password != "explicitpass" {
+		t.Errorf("explicit params should take precedence, got: %+v", c)
+	}
+}
+
 func TestBuildURL(t *testing.T) {
-	c := NewClient("box.example.com", "user", "pass")
+	c, _ := NewClient("box.example.com", "user", "pass")
 
 	tests := []struct {
 		name, recordType, want string
@@ -153,7 +219,10 @@ func TestErrorResponse(t *testing.T) {
 
 // testClient builds a Client pointed at the test server's host.
 func testClient(srv *httptest.Server) *Client {
-	c := NewClient(strings.TrimPrefix(srv.URL, "http://"), "user@example.com", "secret")
+	c, err := NewClient(strings.TrimPrefix(srv.URL, "http://"), "user@example.com", "secret")
+	if err != nil {
+		panic(err)
+	}
 	c.httpClient = srv.Client()
 	// Override buildURL to use http instead of https for the test server.
 	// We do this by wrapping the httpClient transport (no-op) and patching