[fine] Ignore tests sometimes

fine/build.rs

@@ -10,6 +10,7 @@ fn generate_test_for_file(path: PathBuf) -> String {
     let display_path = path.display().to_string();
 
     // Start iterating over lines and processing directives....
+    let mut disabled = quote! {};
     let mut assertions = Vec::new();
     let mut lines = contents.lines();
     while let Some(line) = lines.next() {
@@ -19,7 +20,9 @@ fn generate_test_for_file(path: PathBuf) -> String {
         };
 
         let line = line.trim();
-        if line == "@concrete:" {
+        if line == "@disabled" {
+            disabled = quote! { #[ignore] };
+        } else if line == "@concrete:" {
             let mut concrete = String::new();
             while let Some(line) = lines.next() {
                 let line = match line.strip_prefix("// | ") {
@@ -65,6 +68,7 @@ fn generate_test_for_file(path: PathBuf) -> String {
 
     let name = format_ident!("{}", path.file_stem().unwrap().to_string_lossy());
     let test_method = quote! {
+        #disabled
         fn #name() {
             let (_tree, _lines) = fine::parser::parse(#contents);
             #(#assertions)*

fine/tests/README.md

@@ -37,6 +37,8 @@ e.g., a test might look like this:
 
 The various assertions are as follows:
 
+- The `// @disabled` directive marks the test as ignored.
+
 - The `// @concrete:` assertion says that the following lines
   (prefixed with `// | `, as above) describe the concrete syntax tree
   of the file after parsing.

fine/tests/expression/empty_statement.fine

@@ -0,0 +1,5 @@
+// @disabled
+// @concrete:
+// |
+
+;