tsk-44: Adding test

src/detection/coverart.rs

@@ -18,3 +18,22 @@ pub fn file_type(filepath: &str) -> Result<String, std::io::Error> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_coverart_file_type() {
+        let directory = String::from(crate::test_util::util::TESTFILEDIRECTORY);
+        let filename = String::from("Sample Tracks 3.png");
+        let filepath = format!("{directory}/{filename}");
+
+        match super::file_type(&filepath) {
+            Ok(filetype) => {
+                assert_eq!(filetype, "png", "The file type of the CoverArt should have been png");
+            }
+            Err(err) => {
+                assert!(false, "Error: {err:?}");
+            }
+        }
+    }
+}