Improve windows support, test more platforms in ci (#9)

This fixes a few bugs on windows. Previously the numbered testdir would
cylcle
too fast as the test runner was not detected correctly.

Also expand CI tests to run on more platforms so we find those things a
bit
faster.

.github/workflows/ci.yml

@@ -29,7 +29,11 @@ jobs:
       - run: cargo doc --no-deps --document-private-items
 
   test:
-    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@stable

src/numbered_dir.rs

@@ -314,8 +314,13 @@ mod tests {
         assert!(dir_0.path().is_dir());
         assert!(dir_1.path().is_dir());
 
-        let current = fs::read_link(parent.path().join("base-current")).unwrap();
-        assert_eq!(dir_1.path(), current);
+        // We know that on windows the first symlink probably didn't get removed, symlinks
+        // are best-effort there.
+        #[cfg(target_family = "unix")]
+        {
+            let current = fs::read_link(parent.path().join("base-current")).unwrap();
+            assert_eq!(dir_1.path(), current);
+        }
     }
 
     #[test]

src/private.rs

@@ -20,6 +20,18 @@ const CARGO_PID_FILE_NAME: &str = "cargo-pid";
 /// Whether we are a cargo sub-process.
 static CARGO_PID: Lazy<Option<Pid>> = Lazy::new(cargo_pid);
 
+#[cfg(target_family = "unix")]
+const CARGO_NAME: &str = "cargo";
+
+#[cfg(target_family = "unix")]
+const NEXTEST_NAME: &str = "cargo-nextest";
+
+#[cfg(target_family = "windows")]
+const CARGO_NAME: &str = "cargo.exe";
+
+#[cfg(target_family = "windows")]
+const NEXTEST_NAME: &str = "cargo-nextest.exe";
+
 /// Returns the process ID of our parent Cargo process.
 ///
 /// If our parent process is not Cargo, `None` is returned.
@@ -43,7 +55,7 @@ fn cargo_pid() -> Option<Pid> {
     let parent = sys.process(ppid)?;
     let parent_exe = parent.exe();
     let parent_file_name = parent_exe.file_name()?;
-    if parent_file_name == OsStr::new("cargo") || parent_file_name == OsStr::new("cargo-nextest") {
+    if parent_file_name == OsStr::new(CARGO_NAME) || parent_file_name == OsStr::new(NEXTEST_NAME) {
         Some(parent.pid())
     } else if parent_file_name == OsStr::new("rustdoc") {
         let ppid = parent.parent()?;
@@ -127,7 +139,10 @@ pub fn extract_test_name_from_backtrace(module_path: &str) -> String {
             }
         }
     }
-    panic!("Cannot determine test name from backtrace");
+
+    // We know that on windows doc tests fall through as the module_path is something like
+    // "rust_out" which is not very useful.  We'll have to just use something.
+    String::from("unknown_test")
 }
 
 #[cfg(test)]