Factor out rules parsing

Author: jrmuizel

crates/ra_mbe/src/lib.rs

@@ -161,6 +161,18 @@ impl_froms!(TokenTree: Leaf, Subtree);
     )
     }
 
+    fn create_rules(macro_definition: &str) -> MacroRules {
+        let source_file = ast::SourceFile::parse(macro_definition);
+        let macro_definition = source_file
+            .syntax()
+            .descendants()
+            .find_map(ast::MacroCall::cast)
+            .unwrap();
+
+        let definition_tt = ast_to_token_tree(macro_definition.token_tree().unwrap()).unwrap();
+        crate::MacroRules::parse(&definition_tt).unwrap()
+    }
+
     fn assert_expansion(rules: &MacroRules, invocation: &str, expansion: &str) {
         let source_file = ast::SourceFile::parse(invocation);
         let macro_invocation = source_file
@@ -177,7 +189,8 @@ impl_froms!(TokenTree: Leaf, Subtree);
 
     #[test]
     fn test_fail_match_pattern_by_first_token() {
-        let macro_definition = r#"
+        let rules = create_rules(
+            r#"
         macro_rules! foo {
             ($ i:ident) => (
                 mod $ i {}
@@ -189,17 +202,8 @@ impl_froms!(TokenTree: Leaf, Subtree);
                 struct $ i;
             )
         }
-"#;
-
-        let source_file = ast::SourceFile::parse(macro_definition);
-        let macro_definition = source_file
-            .syntax()
-            .descendants()
-            .find_map(ast::MacroCall::cast)
-            .unwrap();
-
-        let definition_tt = ast_to_token_tree(macro_definition.token_tree().unwrap()).unwrap();
-        let rules = crate::MacroRules::parse(&definition_tt).unwrap();
+"#,
+        );
 
         assert_expansion(&rules, "foo! { foo }", "mod foo {}");
         assert_expansion(&rules, "foo! { = bar }", "fn bar () {}");
@@ -208,7 +212,8 @@ impl_froms!(TokenTree: Leaf, Subtree);
 
     #[test]
     fn test_fail_match_pattern_by_last_token() {
-        let macro_definition = r#"
+        let rules = create_rules(
+            r#"
         macro_rules! foo {
             ($ i:ident) => (
                 mod $ i {}
@@ -220,17 +225,8 @@ impl_froms!(TokenTree: Leaf, Subtree);
                 struct $ i;
             )
         }
-"#;
-
-        let source_file = ast::SourceFile::parse(macro_definition);
-        let macro_definition = source_file
-            .syntax()
-            .descendants()
-            .find_map(ast::MacroCall::cast)
-            .unwrap();
-
-        let definition_tt = ast_to_token_tree(macro_definition.token_tree().unwrap()).unwrap();
-        let rules = crate::MacroRules::parse(&definition_tt).unwrap();
+"#,
+        );
 
         assert_expansion(&rules, "foo! { foo }", "mod foo {}");
         assert_expansion(&rules, "foo! { bar = }", "fn bar () {}");