Enforce one aconfig_declaration per aconfig package

Bug: b/319121098
Change-Id: Ibe3f1587ed7754f00f464cf385ce51ee9a142412
diff --git a/aconfig/all_aconfig_declarations_test.go b/aconfig/all_aconfig_declarations_test.go
new file mode 100644
index 0000000..0b2021e
--- /dev/null
+++ b/aconfig/all_aconfig_declarations_test.go
@@ -0,0 +1,48 @@
+// Copyright 2024 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package aconfig
+
+import (
+	"testing"
+
+	"android/soong/android"
+)
+
+func TestTwoAconfigDeclarationsPerPackage(t *testing.T) {
+	bp := `
+		aconfig_declarations {
+			name: "module_name.foo",
+			package: "com.example.package",
+			container: "com.android.foo",
+			srcs: [
+				"foo.aconfig",
+			],
+		}
+
+		aconfig_declarations {
+			name: "module_name.bar",
+			package: "com.example.package",
+			container: "com.android.foo",
+			srcs: [
+				"bar.aconfig",
+			],
+		}
+	`
+	errMsg := "Only one aconfig_declarations allowed for each package."
+	android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents).
+		ExtendWithErrorHandler(android.FixtureExpectsOneErrorPattern(errMsg)).
+		RunTestWithBp(t, bp)
+}