diff --git a/tests/cache_check.rs b/tests/cache_check.rs
index d729542..3aa724f 100644
--- a/tests/cache_check.rs
+++ b/tests/cache_check.rs
@@ -67,7 +67,7 @@ impl<'a> InputProgram<'a> for CacheCheck {
     }
 }
 
-impl<'a> BinaryInputProgram<'_> for CacheCheck {}
+impl<'a> MetadataReader<'a> for CacheCheck {}
 
 //------------------------------------------
 
diff --git a/tests/common/input_arg.rs b/tests/common/input_arg.rs
index 3453f24..7ef7e69 100644
--- a/tests/common/input_arg.rs
+++ b/tests/common/input_arg.rs
@@ -182,7 +182,7 @@ macro_rules! test_unreadable_input_file {
 
 pub fn test_help_message_for_tiny_input_file<'a, P>() -> Result<()>
 where
-    P: BinaryInputProgram<'a>,
+    P: MetadataReader<'a>,
 {
     let mut td = TestDir::new()?;
 
@@ -209,7 +209,7 @@ macro_rules! test_help_message_for_tiny_input_file {
 
 pub fn test_spot_xml_data<'a, P>() -> Result<()>
 where
-    P: BinaryInputProgram<'a>,
+    P: MetadataReader<'a>,
 {
     let mut td = TestDir::new()?;
 
diff --git a/tests/common/output_option.rs b/tests/common/output_option.rs
index e4e7695..57028f1 100644
--- a/tests/common/output_option.rs
+++ b/tests/common/output_option.rs
@@ -33,12 +33,12 @@ macro_rules! test_missing_output_option {
 
 pub fn test_output_file_not_found<'a, P>() -> Result<()>
 where
-    P: OutputProgram<'a>,
+    P: MetadataWriter<'a>,
 {
     let mut td = TestDir::new()?;
     let input = P::mk_valid_input(&mut td)?;
     let stderr = run_fail(P::path(), args!["-i", &input, "-o", "no-such-file"])?;
-    assert!(stderr.contains(<P as OutputProgram>::file_not_found()));
+    assert!(stderr.contains(<P as MetadataWriter>::file_not_found()));
     Ok(())
 }
 
@@ -105,7 +105,7 @@ macro_rules! test_unwritable_output_file {
 // currently thin/cache_restore only
 pub fn test_tiny_output_file<'a, P>() -> Result<()>
 where
-    P: BinaryOutputProgram<'a>,
+    P: MetadataWriter<'a>,
 {
     let mut td = TestDir::new()?;
     let input = P::mk_valid_input(&mut td)?;
diff --git a/tests/common/program.rs b/tests/common/program.rs
index 51b63e9..0414b3d 100644
--- a/tests/common/program.rs
+++ b/tests/common/program.rs
@@ -30,14 +30,20 @@ pub trait InputProgram<'a>: Program<'a> {
     fn corrupted_input() -> &'a str;
 }
 
-pub trait BinaryInputProgram<'a>: InputProgram<'a> {}
+pub trait MetadataReader<'a>: InputProgram<'a> {}
 
 pub trait OutputProgram<'a>: InputProgram<'a> {
     // error messages
     fn missing_output_arg() -> &'a str;
+}
+
+// programs that write existed files
+pub trait MetadataWriter<'a>: OutputProgram<'a> {
+    // error messages
     fn file_not_found() -> &'a str;
 }
 
-pub trait BinaryOutputProgram<'a>: OutputProgram<'a> {}
+// programs that create output files (O_CREAT)
+pub trait MetadataCreator<'a>: OutputProgram<'a> {}
 
 //------------------------------------------
diff --git a/tests/thin_check.rs b/tests/thin_check.rs
index 1f1db46..608a5cb 100644
--- a/tests/thin_check.rs
+++ b/tests/thin_check.rs
@@ -70,7 +70,7 @@ impl<'a> InputProgram<'a> for ThinCheck {
     }
 }
 
-impl<'a> BinaryInputProgram<'_> for ThinCheck {}
+impl<'a> MetadataReader<'_> for ThinCheck {}
 
 //------------------------------------------
 
diff --git a/tests/thin_metadata_pack.rs b/tests/thin_metadata_pack.rs
index dea1eff..b45c1bc 100644
--- a/tests/thin_metadata_pack.rs
+++ b/tests/thin_metadata_pack.rs
@@ -74,10 +74,6 @@ impl<'a> InputProgram<'a> for ThinMetadataPack {
 }
 
 impl<'a> OutputProgram<'a> for ThinMetadataPack {
-    fn file_not_found() -> &'a str {
-        rust_msg::FILE_NOT_FOUND
-    }
-
     fn missing_output_arg() -> &'a str {
         rust_msg::MISSING_OUTPUT_ARG
     }
diff --git a/tests/thin_metadata_unpack.rs b/tests/thin_metadata_unpack.rs
index 1292965..fe77f22 100644
--- a/tests/thin_metadata_unpack.rs
+++ b/tests/thin_metadata_unpack.rs
@@ -76,10 +76,6 @@ impl<'a> InputProgram<'a> for ThinMetadataUnpack {
 }
 
 impl<'a> OutputProgram<'a> for ThinMetadataUnpack {
-    fn file_not_found() -> &'a str {
-        rust_msg::FILE_NOT_FOUND
-    }
-
     fn missing_output_arg() -> &'a str {
         rust_msg::MISSING_OUTPUT_ARG
     }
diff --git a/tests/thin_repair.rs b/tests/thin_repair.rs
index 3a37846..eb3ac2d 100644
--- a/tests/thin_repair.rs
+++ b/tests/thin_repair.rs
@@ -69,15 +69,17 @@ impl<'a> InputProgram<'a> for ThinRepair {
 }
 
 impl<'a> OutputProgram<'a> for ThinRepair {
-    fn file_not_found() -> &'a str {
-        cpp_msg::FILE_NOT_FOUND
-    }
-
     fn missing_output_arg() -> &'a str {
         cpp_msg::MISSING_OUTPUT_ARG
     }
 }
 
+impl<'a> MetadataWriter<'a> for ThinRepair {
+    fn file_not_found() -> &'a str {
+        cpp_msg::FILE_NOT_FOUND
+    }
+}
+
 //-----------------------------------------
 
 test_accepts_help!(ThinRepair);
diff --git a/tests/thin_restore.rs b/tests/thin_restore.rs
index 65ef87a..b908566 100644
--- a/tests/thin_restore.rs
+++ b/tests/thin_restore.rs
@@ -70,16 +70,16 @@ impl<'a> InputProgram<'a> for ThinRestore {
 }
 
 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 {}
+impl<'a> MetadataWriter<'a> for ThinRestore {
+    fn file_not_found() -> &'a str {
+        msg::FILE_NOT_FOUND
+    }
+}
 
 //-----------------------------------------
 
@@ -93,6 +93,8 @@ test_corrupted_input_data!(ThinRestore);
 test_missing_output_option!(ThinRestore);
 test_tiny_output_file!(ThinRestore);
 
+test_unwritable_output_file!(ThinRestore);
+
 //-----------------------------------------
 
 // TODO: share with cache_restore, era_restore