Cartridge: added tests for error types

cartridge/src/tests.rs

@@ -2,6 +2,58 @@
 mod cartridge_tests {
     use crate::{Cartridge, CartridgeError};
 
+    #[test]
+    fn cartridge_file_not_found() {
+        let err = Cartridge::from_file("./file/does/not/exists.nes")
+            .err()
+            .expect("Should get an error as the cartridge file does not exists");
+
+        if let CartridgeError::FileError(file_err) = err {
+            assert_eq!(file_err.kind(), std::io::ErrorKind::NotFound);
+        } else {
+            panic!("Should get file not found error");
+        }
+    }
+
+    #[test]
+    fn cartridge_extension_error_file() {
+        let err = Cartridge::from_file("./file/does/not/exists.notnes")
+            .err()
+            .expect("Should get an error as the cartridge has extension error");
+
+        if let CartridgeError::ExtensionError = err {
+            // passed
+        } else {
+            panic!("Should get extension error");
+        }
+    }
+
+    #[test]
+    fn cartridge_wrong_header() {
+        let err = Cartridge::from_file("./tests/roms/test_wrong_header.nes")
+            .err()
+            .expect("Should get an error as the cartridge has wrong header");
+
+        if let CartridgeError::HeaderError = err {
+            // passed
+        } else {
+            panic!("Should get header error");
+        }
+    }
+
+    #[test]
+    fn cartridge_large_file() {
+        let err = Cartridge::from_file("./tests/roms/test_large_file.nes")
+            .err()
+            .expect("Should get an error as the cartridge file is larger than expected");
+
+        if let CartridgeError::TooLargeFile(exceeded_size) = err {
+            assert_eq!(exceeded_size, 1);
+        } else {
+            panic!("Should get too large file error");
+        }
+    }
+
     #[test]
     fn test_ines1_cartridge_read() -> Result<(), CartridgeError> {
         let cartridge = Cartridge::from_file("./tests/roms/test_creation.nes")?;