add tests for test discovery

.gitignore

@@ -4,3 +4,4 @@
 # Python
 **/__pycache__
 *.pyc
+**/.venv

ruff.toml

@@ -0,0 +1 @@
+exclude = ["./tests/discovery/invalid_syntax.py"]

src/discovery.rs

@@ -114,9 +114,10 @@ pub fn find_tests(paths: &[PathBuf], exclude: &[PathBuf]) -> DiscoveredTests {
   // Exclude specified from the search
   let mut exclude_override = ignore::overrides::OverrideBuilder::new("");
   for path in exclude {
-    exclude_override
-      .add(&format!("!{}", path.to_string_lossy()))
-      .unwrap();
+    let path = path.to_string_lossy();
+    // Unexpected behaviour when relative paths start with "./" so remove if exists
+    let path = path.trim_matches(['.', '/']);
+    exclude_override.add(&format!("!{path}",)).unwrap();
   }
   builder.overrides(exclude_override.build().unwrap());
 

tests/discovery.rs

@@ -0,0 +1,53 @@
+use assert_cmd::Command;
+use std::env;
+
+fn count_tests_run(args: &[&str]) -> usize {
+  let cmd_output = Command::cargo_bin(env!("CARGO_PKG_NAME"))
+    .unwrap()
+    .args(args)
+    .arg("--output=json")
+    .output()
+    .unwrap();
+
+  let stdout = String::from_utf8(cmd_output.stdout).unwrap();
+  stdout.lines().count()
+}
+
+#[test]
+fn find_all_tests_in_folder() {
+  assert_eq!(count_tests_run(&["./tests/discovery/"]), 6);
+}
+
+#[test]
+fn non_existant_paths() {
+  assert_eq!(count_tests_run(&["./discovery/tests/"]), 0);
+  assert_eq!(count_tests_run(&["./discovery/tests/x.py"]), 0);
+}
+
+#[test]
+fn files_run_individually() {
+  assert_eq!(count_tests_run(&["./tests/discovery/a.py"]), 1);
+  assert_eq!(count_tests_run(&["./tests/discovery/b.py"]), 2);
+  assert_eq!(count_tests_run(&["./tests/discovery/c.py"]), 3);
+}
+
+#[test]
+fn exclude_single_file() {
+  let base_path = "./tests/discovery";
+  for (file, test_count) in [("a", 5), ("b", 4), ("c", 3)] {
+    let relative = format!("--exclude=./tests/discovery/{file}.py");
+    let path = format!("--exclude=tests/discovery/{file}.py");
+    let glob_file = format!("--exclude=**/{file}.py");
+    let file = format!("--exclude={file}.py");
+
+    assert_eq!(count_tests_run(&[base_path, &relative]), test_count);
+    assert_eq!(count_tests_run(&[base_path, &path]), test_count);
+    assert_eq!(count_tests_run(&[base_path, &glob_file]), test_count);
+    assert_eq!(count_tests_run(&[base_path, &file]), test_count);
+  }
+}
+
+#[test]
+fn file_with_invalid_syntax() {
+  assert_eq!(count_tests_run(&["./tests/discovery/invalid_syntax.py"]), 0);
+}

tests/discovery/a.py

@@ -0,0 +1,2 @@
+def test_one():
+    pass

tests/discovery/b.py

@@ -0,0 +1,6 @@
+def test_one():
+    pass
+
+
+def test_two():
+    pass

tests/discovery/c.py

@@ -0,0 +1,10 @@
+def test_one():
+    pass
+
+
+def test_two():
+    pass
+
+
+def test_three():
+    pass

tests/discovery/invalid_syntax.py

@@ -0,0 +1,11 @@
+# ruff: noqa
+
+use std::{
+  ffi::CStr,
+  ops,
+  time::{Duration, Instant},
+};
+
+
+def test_one():
+  pass