NO-JIRA: [Rust] Fix build errors with 1.78.0-nightly (0ecbd0605 2024-02-25)

Extract the test trait impls out of the test function body.
No user facing changes!

```
error: non-local `impl` definition, they should be avoided as they go against expectation
  --> avro/tests/validators.rs:42:5
   |
42 | /     impl SchemaNamespaceValidator for CustomValidator {
43 | |         fn validate(&self, _ns: &str) -> AvroResult<()> {
44 | |             Ok(())
45 | |         }
46 | |     }
   | |_____^
   |
   = help: move this `impl` block outside the of the current function `avro_3900_custom_validator_with_spec_invalid_names`
   = note: an `impl` definition is non-local if it is nested inside an item and neither the type nor the trait are at the same nesting level as the `impl` block
   = note: one exception to the rule are anon-const (`const _: () = { ... }`) at top-level module and anon-const at the same nesting as the trait or type
   = note: this lint may become deny-by-default in the edition 2024 and higher, see the tracking issue <rust-lang/rust#120363>
```

Signed-off-by: Martin Tzvetanov Grigorov <[email protected]>

Author: martin-g

avro/tests/validators.rs

@@ -28,35 +28,35 @@ use apache_avro_test_helper::TestResult;
 
 struct CustomValidator;
 
-#[test]
-fn avro_3900_custom_validator_with_spec_invalid_names() -> TestResult {
-    // Setup the custom validators before the schema is parsed
-    // because the parsing will trigger the validation and will
-    // setup the default validator (SpecificationValidator)!
-    impl SchemaNameValidator for CustomValidator {
-        fn validate(&self, schema_name: &str) -> AvroResult<(String, Namespace)> {
-            Ok((schema_name.to_string(), None))
-        }
+// Setup the custom validators before the schema is parsed
+// because the parsing will trigger the validation and will
+// setup the default validator (SpecificationValidator)!
+impl SchemaNameValidator for CustomValidator {
+    fn validate(&self, schema_name: &str) -> AvroResult<(String, Namespace)> {
+        Ok((schema_name.to_string(), None))
     }
+}
 
-    impl SchemaNamespaceValidator for CustomValidator {
-        fn validate(&self, _ns: &str) -> AvroResult<()> {
-            Ok(())
-        }
+impl SchemaNamespaceValidator for CustomValidator {
+    fn validate(&self, _ns: &str) -> AvroResult<()> {
+        Ok(())
     }
+}
 
-    impl EnumSymbolNameValidator for CustomValidator {
-        fn validate(&self, _ns: &str) -> AvroResult<()> {
-            Ok(())
-        }
+impl EnumSymbolNameValidator for CustomValidator {
+    fn validate(&self, _ns: &str) -> AvroResult<()> {
+        Ok(())
     }
+}
 
-    impl RecordFieldNameValidator for CustomValidator {
-        fn validate(&self, _ns: &str) -> AvroResult<()> {
-            Ok(())
-        }
+impl RecordFieldNameValidator for CustomValidator {
+    fn validate(&self, _ns: &str) -> AvroResult<()> {
+        Ok(())
     }
+}
 
+#[test]
+fn avro_3900_custom_validator_with_spec_invalid_names() -> TestResult {
     assert!(set_schema_name_validator(Box::new(CustomValidator)).is_ok());
     assert!(set_schema_namespace_validator(Box::new(CustomValidator)).is_ok());
     assert!(set_enum_symbol_name_validator(Box::new(CustomValidator)).is_ok());

avro_test_helper/src/lib.rs

@@ -23,7 +23,7 @@ thread_local! {
     // The unit tests run in parallel
     // We need to keep the log messages in a thread-local variable
     // and clear them after assertion
-    pub(crate) static LOG_MESSAGES: RefCell<Vec<String>> = RefCell::new(Vec::new());
+    pub(crate) static LOG_MESSAGES: RefCell<Vec<String>> = const { RefCell::new(Vec::new()) };
 }
 
 pub mod logger;