test(nproc): add a test

tests/by-util/test_nproc.rs

@@ -1 +1,58 @@
-// ToDO: add tests
+use crate::common::util::*;
+
+#[test]
+fn test_nproc() {
+    let (_, mut ucmd) = at_and_ucmd!();
+    let result = ucmd.run();
+    assert!(result.success);
+    let nproc: u8 = result.stdout.trim().parse().unwrap();
+    assert!(nproc > 0);
+}
+
+
+#[test]
+fn test_nproc_all_omp() {
+    let (_, mut ucmd) = at_and_ucmd!();
+    let result = ucmd.arg("--all").run();
+    assert!(result.success);
+    let nproc: u8 = result.stdout.trim().parse().unwrap();
+    assert!(nproc > 0);
+
+
+    let result = TestScenario::new(util_name!())
+    .ucmd_keepenv()
+    .env("OMP_NUM_THREADS", "1")
+    .run();
+    assert!(result.success);
+    let nproc_omp: u8 = result.stdout.trim().parse().unwrap();
+    assert!(nproc-1 == nproc_omp);
+
+
+    let result = TestScenario::new(util_name!())
+    .ucmd_keepenv()
+    .env("OMP_NUM_THREADS", "1") // Has no effect
+    .arg("--all")
+    .run();
+    assert!(result.success);
+    let nproc_omp: u8 = result.stdout.trim().parse().unwrap();
+    assert!(nproc == nproc_omp);
+}
+
+#[test]
+fn test_nproc_ignore() {
+    let (_, mut ucmd) = at_and_ucmd!();
+    let result = ucmd.run();
+    assert!(result.success);
+    let nproc: u8 = result.stdout.trim().parse().unwrap();
+    if nproc > 1 {
+        // Ignore all CPU but one
+        let result = TestScenario::new(util_name!())
+            .ucmd_keepenv()
+            .arg("--ignore")
+            .arg((nproc - 1).to_string())
+            .run();
+        assert!(result.success);
+        let nproc: u8 = result.stdout.trim().parse().unwrap();
+        assert!(nproc == 1);
+    }
+}