Add additional tests to ensure threading behavior is correct

Author: LukasKalbertodt

tests/main_thread.rs

@@ -0,0 +1,65 @@
+use std::time::Duration;
+use libtest_mimic::{Trial, Arguments};
+
+
+#[test]
+fn check_test_on_main_thread() {
+    let outer_thread = std::thread::current().id();
+
+    let mut args = Arguments::default();
+    args.test_threads = Some(1);
+    let conclusion = libtest_mimic::run(&args, vec![Trial::test("check", move || {
+        assert_eq!(outer_thread, std::thread::current().id());
+        Ok(())
+    })]);
+
+    assert_eq!(conclusion.num_passed, 1);
+}
+
+#[test]
+fn all_tests_run_on_single_thread() {
+    let mut args = Arguments::default();
+    args.test_threads = Some(1);
+    let trials = vec![
+        Trial::test("a", move || Ok(())),
+        Trial::test("b", move || Ok(())),
+        Trial::test("c", move || Ok(())),
+    ];
+    let conclusion = libtest_mimic::run(&args, trials);
+    assert_eq!(conclusion.num_passed, 3);
+}
+
+#[test]
+fn all_tests_run_on_two_threads() {
+    let mut args = Arguments::default();
+    args.test_threads = Some(2);
+    let trials = vec![
+        Trial::test("a", move || Ok(())),
+        Trial::test("b", move || Ok(())),
+        Trial::test("c", move || Ok(())),
+        Trial::test("d", move || Ok(())),
+        Trial::test("e", move || Ok(())),
+    ];
+    let conclusion = libtest_mimic::run(&args, trials);
+    assert_eq!(conclusion.num_passed, 5);
+}
+
+// I know this is not a super clean test, but I think spurious failures should
+// be veeeery limited. The value this test provides outweights the potential
+// jankiness I think.
+#[test]
+fn multi_threads_are_used() {
+    let mut args = Arguments::default();
+    args.test_threads = Some(4);
+    let trials = vec![
+        Trial::test("a", move || { std::thread::sleep(Duration::from_secs(1)); Ok(()) }),
+        Trial::test("b", move || { std::thread::sleep(Duration::from_secs(1)); Ok(()) }),
+        Trial::test("c", move || { std::thread::sleep(Duration::from_secs(1)); Ok(()) }),
+        Trial::test("d", move || { std::thread::sleep(Duration::from_secs(1)); Ok(()) }),
+    ];
+    let before = std::time::Instant::now();
+    let _ = libtest_mimic::run(&args, trials);
+    if before.elapsed() >= Duration::from_secs(2) {
+        panic!("Seems like tests are not executed in parallel");
+    }
+}