[tests] Use traits to specify test parameters

To deal with variety in target attributes and their expected outputs,
the test parameters are categorized into traits, thus the test program
could define test parameters in a more structured way, without having
to pass multiple tightly-coupled parameters to test functions.

tests/thin_restore.rs

@@ -23,15 +23,71 @@ const USAGE: &str = "Usage: thin_restore [options]\n\
 
 //------------------------------------------
 
-test_accepts_help!(THIN_RESTORE, USAGE);
-test_accepts_version!(THIN_RESTORE);
+struct ThinRestore;
 
-test_missing_input_option!(THIN_RESTORE);
-test_input_file_not_found!(THIN_RESTORE, OPTION);
-test_corrupted_input_data!(THIN_RESTORE, OPTION);
+impl<'a> Program<'a> for ThinRestore {
+    fn name() -> &'a str {
+        "thin_restore"
+    }
 
-test_missing_output_option!(THIN_RESTORE, mk_valid_xml);
-test_tiny_output_file!(THIN_RESTORE, mk_valid_xml);
+    fn path() -> &'a str {
+        THIN_RESTORE
+    }
+
+    fn usage() -> &'a str {
+        USAGE
+    }
+
+    fn arg_type() -> ArgType {
+        ArgType::IoOptions
+    }
+
+    fn bad_option_hint(option: &str) -> String {
+        msg::bad_option_hint(option)
+    }
+}
+
+impl<'a> InputProgram<'a> for ThinRestore {
+    fn mk_valid_input(td: &mut TestDir) -> Result<std::path::PathBuf> {
+        mk_valid_md(td)
+    }
+
+    fn file_not_found() -> &'a str {
+        msg::FILE_NOT_FOUND
+    }
+
+    fn missing_input_arg() -> &'a str {
+        msg::MISSING_INPUT_ARG
+    }
+
+    fn corrupted_input() -> &'a str {
+        "" // we don't intent to verify error messages of XML parsing
+    }
+}
+
+impl<'a> OutputProgram<'a> for ThinRestore {
+    fn file_not_found() -> &'a str {
+        msg::FILE_NOT_FOUND
+    }
+
+    fn missing_output_arg() -> &'a str {
+        msg::MISSING_OUTPUT_ARG
+    }
+}
+
+impl<'a> BinaryOutputProgram<'_> for ThinRestore {}
+
+//-----------------------------------------
+
+test_accepts_help!(ThinRestore);
+test_accepts_version!(ThinRestore);
+
+test_missing_input_option!(ThinRestore);
+test_input_file_not_found!(ThinRestore);
+test_corrupted_input_data!(ThinRestore);
+
+test_missing_output_option!(ThinRestore);
+test_tiny_output_file!(ThinRestore);
 
 //-----------------------------------------