fs test: factor some common code

Author: RalfJung

tests/run-pass/fs.rs

@@ -15,13 +15,18 @@ fn main() {
     test_rename();
 }
 
-fn test_file() {
+/// Prepare: compute filename and make sure the file does not exist.
+fn prepare(filename: &str) -> PathBuf {
     let tmp = std::env::temp_dir();
-    let filename = PathBuf::from("miri_test_fs_file.txt");
-    let path = tmp.join(&filename);
-    let bytes = b"Hello, World!\n";
+    let path = tmp.join(filename);
     // Clean the paths for robustness.
     remove_file(&path).ok();
+    path
+}
+
+fn test_file() {
+    let path = prepare("miri_test_fs_file.txt");
+    let bytes = b"Hello, World!\n";
 
     // Test creating, writing and closing a file (closing is tested when `file` is dropped).
     let mut file = File::create(&path).unwrap();
@@ -45,12 +50,8 @@ fn test_file() {
 }
 
 fn test_file_clone() {
-    let tmp = std::env::temp_dir();
-    let filename = PathBuf::from("miri_test_fs_file_clone.txt");
-    let path = tmp.join(&filename);
+    let path = prepare("miri_test_fs_file_clone.txt");
     let bytes = b"Hello, World!\n";
-    // Clean the paths for robustness.
-    remove_file(&path).ok();
 
     let mut file = File::create(&path).unwrap();
     file.write(bytes).unwrap();
@@ -68,12 +69,8 @@ fn test_file_clone() {
 }
 
 fn test_seek() {
-    let tmp = std::env::temp_dir();
-    let filename = PathBuf::from("miri_test_fs_seek.txt");
-    let path = tmp.join(&filename);
+    let path = prepare("miri_test_fs_seek.txt");
     let bytes = b"Hello, World!\n";
-    // Clean the paths for robustness.
-    remove_file(&path).ok();
 
     let mut file = File::create(&path).unwrap();
     file.write(bytes).unwrap();
@@ -113,35 +110,26 @@ fn check_metadata(bytes: &[u8], path: &Path) -> Result<()> {
 }
 
 fn test_metadata() {
-    let tmp = std::env::temp_dir();
-    let filename = PathBuf::from("miri_test_fs_metadata.txt");
-    let path = tmp.join(&filename);
+    let path = prepare("miri_test_fs_metadata.txt");
     let bytes = b"Hello, World!\n";
-    // Clean the paths for robustness.
-    remove_file(&path).ok();
 
     let mut file = File::create(&path).unwrap();
     file.write(bytes).unwrap();
 
     // Test that metadata of an absolute path is correct.
     check_metadata(bytes, &path).unwrap();
     // Test that metadata of a relative path is correct.
-    std::env::set_current_dir(&tmp).unwrap();
-    check_metadata(bytes, &filename).unwrap();
+    std::env::set_current_dir(path.parent().unwrap()).unwrap();
+    check_metadata(bytes, Path::new(path.file_name().unwrap())).unwrap();
 
     // Removing file should succeed.
     remove_file(&path).unwrap();
 }
 
 fn test_symlink() {
-    let tmp = std::env::temp_dir();
-    let filename = PathBuf::from("miri_test_fs_link_target.txt");
-    let path = tmp.join(&filename);
-    let symlink_path = tmp.join("miri_test_fs_symlink.txt");
+    let path = prepare("miri_test_fs_link_target.txt");
+    let symlink_path = prepare("miri_test_fs_symlink.txt");
     let bytes = b"Hello, World!\n";
-    // Clean the paths for robustness.
-    remove_file(&path).ok();
-    remove_file(&symlink_path).ok();
 
     let mut file = File::create(&path).unwrap();
     file.write(bytes).unwrap();
@@ -165,12 +153,8 @@ fn test_symlink() {
 }
 
 fn test_errors() {
-    let tmp = std::env::temp_dir();
-    let filename = PathBuf::from("miri_test_fs_errors.txt");
-    let path = tmp.join(&filename);
+    let path = prepare("miri_test_fs_errors.txt");
     let bytes = b"Hello, World!\n";
-    // Clean the paths for robustness.
-    remove_file(&path).ok();
 
     // The following tests also check that the `__errno_location()` shim is working properly.
     // Opening a non-existing file should fail with a "not found" error.
@@ -182,13 +166,10 @@ fn test_errors() {
 }
 
 fn test_rename() {
-    let tmp = std::env::temp_dir();
     // Renaming a file should succeed.
-    let path1 = tmp.join("miri_test_fs_rename_source.txt");
-    let path2 = tmp.join("miri_test_fs_rename_destination.txt");
-    // Clean files for robustness.
-    remove_file(&path1).ok();
-    remove_file(&path2).ok();
+    let path1 = prepare("miri_test_fs_rename_source.txt");
+    let path2 = prepare("miri_test_fs_rename_destination.txt");
+
     let file = File::create(&path1).unwrap();
     drop(file);
     rename(&path1, &path2).unwrap();