tsk-44: Identify CoverArt type (#46)

Closes #44

Reviewed-on: #46
Co-authored-by: phoenix <kundeng00@pm.me>
Co-committed-by: phoenix <kundeng00@pm.me>

src/detection/coverart.rs

@@ -0,0 +1,32 @@
+/// Gets the file type of a CoverArt given it's path
+pub fn file_type(filepath: &str) -> Result<String, std::io::Error> {
+    match imghdr::from_file(filepath) {
+        Ok(Some(imghdr::Type::Jpeg)) => Ok(String::from("jpeg")),
+        Ok(Some(imghdr::Type::Png)) => Ok(String::from("png")),
+        Ok(None) => Err(std::io::Error::other("Image file not supported")),
+        Err(err) => Err(err),
+        _ => Err(std::io::Error::other("Image file not supported")),
+    }
+}
+
+#[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:?}");
+            }
+        }
+    }
+}