aconfig: add test utilities

Create a test utility function to create a Cache from the files in
testdata/*. A follow-up CL will update the unit tests to use this
instead of creating their own caches.

Bug: 283910447
Test: atest aconfig.test
Change-Id: Ice5064eadb0babde5eb38d292330d213ab136d96

tools/aconfig/src/codegen_rust.rs

@@ -79,28 +79,10 @@ fn create_template_parsed_flag(namespace: &str, item: &Item) -> TemplateParsedFl
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::commands::{create_cache, Input, Source};
 
     #[test]
     fn test_generate_rust_code() {
-        let cache = create_cache(
-            "test",
-            vec![Input {
-                source: Source::File("testdata/test.aconfig".to_string()),
-                reader: Box::new(include_bytes!("../testdata/test.aconfig").as_slice()),
-            }],
-            vec![
-                Input {
-                    source: Source::File("testdata/first.values".to_string()),
-                    reader: Box::new(include_bytes!("../testdata/first.values").as_slice()),
-                },
-                Input {
-                    source: Source::File("testdata/test.aconfig".to_string()),
-                    reader: Box::new(include_bytes!("../testdata/second.values").as_slice()),
-                },
-            ],
-        )
-        .unwrap();
+        let cache = crate::test::create_cache();
         let generated = generate_rust_code(&cache).unwrap();
         assert_eq!("src/lib.rs", format!("{}", generated.path.display()));
         let expected = r#"

tools/aconfig/src/main.rs

@@ -33,6 +33,9 @@ mod codegen_rust;
 mod commands;
 mod protos;
 
+#[cfg(test)]
+mod test;
+
 use crate::cache::Cache;
 use commands::{DumpFormat, Input, OutputFile, Source};
 

tools/aconfig/src/test.rs

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#[cfg(test)]
+pub mod test_utils {
+    use crate::cache::Cache;
+    use crate::commands::{Input, Source};
+
+    pub fn create_cache() -> Cache {
+        crate::commands::create_cache(
+            "test",
+            vec![Input {
+                source: Source::File("testdata/test.aconfig".to_string()),
+                reader: Box::new(include_bytes!("../testdata/test.aconfig").as_slice()),
+            }],
+            vec![
+                Input {
+                    source: Source::File("testdata/first.values".to_string()),
+                    reader: Box::new(include_bytes!("../testdata/first.values").as_slice()),
+                },
+                Input {
+                    source: Source::File("testdata/test.aconfig".to_string()),
+                    reader: Box::new(include_bytes!("../testdata/second.values").as_slice()),
+                },
+            ],
+        )
+        .unwrap()
+    }
+}
+
+#[cfg(test)]
+pub use test_utils::*;