Test copying symlinks

Cargo.toml

@@ -124,6 +124,7 @@ exclude = [
     "testdata/small_well_tested",
     "testdata/strict_warnings",
     "testdata/struct_with_no_default",
+    "testdata/symlink",
     "testdata/unapply",
     "testdata/unsafe",
     "testdata/well_tested",

testdata/symlink/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "cargo-mutants-testdata-symlink"
+version = "0.0.0"
+edition = "2021"
+publish = false
+
+[lib]
+doctest = false

testdata/symlink/README.md

@@ -0,0 +1,3 @@
+# testdata/symlink
+
+A source tree that contains a symlink, committed to git. The symlink must exist for the tests to pass. This is used to test that cargo-mutants copies the symlinks correctly, especially on Windows.

testdata/symlink/src/lib.rs

@@ -0,0 +1,15 @@
+use std::path::Path;
+
+fn read_through_symlink() -> String {
+    let path = Path::new("testdata/symlink");
+    assert!(path.is_symlink());
+    std::fs::read_to_string(path).unwrap()
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn read_through_symlink_test() {
+        assert_eq!(super::read_through_symlink().trim(), "Hello, world!");
+    }
+}

testdata/symlink/testdata/symlink

@@ -0,0 +1 @@
+target

testdata/symlink/testdata/target

@@ -0,0 +1 @@
+Hello, world!

tests/cli/build_dir.rs

@@ -30,3 +30,15 @@ fn gitignore_can_be_turned_off() {
         .assert()
         .success();
 }
+
+/// A tree containing a symlink that must exist for the tests to pass works properly.
+///
+/// This runs in-place to avoid any complications from copying the testdata.
+#[test]
+fn tree_with_symlink() {
+    run()
+        .args(["mutants", "-d"])
+        .arg("testdata/symlink")
+        .assert()
+        .success();
+}