Add a unit test for path inferring

tests/test_path_utils.rs

@@ -0,0 +1,38 @@
+#[cfg(test)]
+mod tests {
+    use std::path::Path;
+
+    use rllvm::utils::*;
+
+    #[test]
+    fn test_derive_object_and_bitcode_filepath() {
+        let test_inputs = [
+            (
+                Path::new("/tmp/foo.c"),
+                false,
+                (Path::new("/tmp/.foo.o"), Path::new("/tmp/.foo.o.bc")),
+            ),
+            (
+                Path::new("/tmp/foo.c"),
+                true,
+                (Path::new("/tmp/foo.c.o"), Path::new("/tmp/.foo.o.bc")),
+            ),
+        ];
+
+        assert!(test_inputs.iter().all(
+            |&(
+                src_filepath,
+                is_compile_only,
+                (expected_object_filepath, expected_bitcode_filepath),
+            )| {
+                derive_object_and_bitcode_filepath(src_filepath, is_compile_only).map_or(
+                    false,
+                    |(object_filepath, bitcode_filepath)| {
+                        object_filepath == expected_object_filepath
+                            && bitcode_filepath == expected_bitcode_filepath
+                    },
+                )
+            },
+        ));
+    }
+}