add support for env variables to the DSL

lang/test_server_entity_comparisons.go

@@ -21,7 +21,68 @@ func serverEqual(got, want Server) bool {
 }
 
 func serverSettingEqual(got, want ServerSetting) bool {
-	return stringPtrEqual(got.Host, want.Host) && intPtrEqual(got.Port, want.Port)
+	return configValueEqual(got.Host, want.Host) &&
+		intValueEqual(got.Port, want.Port) &&
+		configValueEqual(got.DatabaseURL, want.DatabaseURL) &&
+		configValueEqual(got.APIKey, want.APIKey) &&
+		configValueEqual(got.SSLCert, want.SSLCert) &&
+		configValueEqual(got.SSLKey, want.SSLKey)
+}
+
+func configValueEqual(got, want *ConfigValue) bool {
+	if got == nil && want == nil {
+		return true
+	}
+	if got == nil || want == nil {
+		return false
+	}
+
+	// Check literal values
+	if got.Literal != nil && want.Literal != nil {
+		return *got.Literal == *want.Literal
+	}
+	if got.Literal != nil || want.Literal != nil {
+		return false
+	}
+
+	// Check environment variables
+	if got.EnvVar != nil && want.EnvVar != nil {
+		return envVarEqual(*got.EnvVar, *want.EnvVar)
+	}
+	return got.EnvVar == nil && want.EnvVar == nil
+}
+
+func intValueEqual(got, want *IntValue) bool {
+	if got == nil && want == nil {
+		return true
+	}
+	if got == nil || want == nil {
+		return false
+	}
+
+	// Check literal values
+	if got.Literal != nil && want.Literal != nil {
+		return *got.Literal == *want.Literal
+	}
+	if got.Literal != nil || want.Literal != nil {
+		return false
+	}
+
+	// Check environment variables
+	if got.EnvVar != nil && want.EnvVar != nil {
+		return envVarEqual(*got.EnvVar, *want.EnvVar)
+	}
+	return got.EnvVar == nil && want.EnvVar == nil
+}
+
+func envVarEqual(got, want EnvVar) bool {
+	if got.Name != want.Name {
+		return false
+	}
+	if got.Required != want.Required {
+		return false
+	}
+	return stringPtrEqual(got.Default, want.Default)
 }
 
 func entityEqual(got, want Entity) bool {