tests: add test on par coverage ordering

tests/coverage.rs

@@ -55,6 +55,51 @@ mod testing {
         Ok(())
     }
 
+    #[test]
+    fn test_coverage_mt() -> Result<()> {
+        let a = "tests/datasets/coverage/coverage_a.bed";
+        let b = "tests/datasets/coverage/coverage_b.bed";
+
+        let mut cmd = Command::cargo_bin("gia")?;
+        let output = cmd
+            .arg("coverage")
+            .arg("-a")
+            .arg(a)
+            .arg("-b")
+            .arg(b)
+            .arg("-@")
+            .arg("4")
+            .output()?;
+        println!("{:?}", output);
+        let num_intervals = output.stdout.split(|&c| c == b'\n').count() - 1;
+        assert_eq!(num_intervals, 10);
+
+        let num_fields = output
+            .stdout
+            .split(|&c| c == b'\n')
+            .next()
+            .unwrap()
+            .split(|&c| c == b'\t')
+            .count();
+        assert_eq!(num_fields, 4);
+
+        let expected = vec![
+            (1, 72, 222, 4),
+            (1, 257, 407, 1),
+            (1, 268, 418, 1),
+            (1, 467, 617, 1),
+            (1, 819, 969, 1),
+            (2, 174, 324, 2),
+            (2, 587, 737, 1),
+            (3, 395, 545, 0),
+            (3, 554, 704, 0),
+            (3, 653, 803, 0),
+        ];
+        let expected_str = build_expected_str(&expected);
+        assert_eq!(output.stdout, expected_str.as_bytes());
+        Ok(())
+    }
+
     #[test]
     fn test_coverage_bed3_bed3() -> Result<()> {
         let a = "tests/datasets/coverage/coverage_a.bed";