Default strings and vectors: Parser + Rust support (#6421)

* Fix tests.cpp

* Parser support for vector/string defaults

* tests and default empty vectors

* addressed comments

* Default strings and vectors for Rust

* Tested Rust more_defaults

* git-clang-format

* add more_defaults_test

* fixed vector default

* removed commented out code

* more unreachable

Co-authored-by: Casper Neo <cneo@google.com>

tests/rust_usage_test/tests/integration_test.rs

@@ -30,6 +30,7 @@ extern crate quickcheck_derive;
 
 mod flexbuffers_tests;
 mod optional_scalars_test;
+mod more_defaults_test;
 
 #[allow(dead_code, unused_imports)]
 #[path = "../../include_test/include_test1_generated.rs"]

tests/rust_usage_test/tests/more_defaults_test.rs

@@ -0,0 +1,26 @@
+#[allow(dead_code, unused_imports)]
+#[path = "../../more_defaults_generated.rs"]
+mod more_defaults_generated;
+use self::more_defaults_generated::*;
+
+#[test]
+fn object_defaults() {
+    assert_eq!(
+        MoreDefaultsT::default(),
+        MoreDefaultsT {
+            ints: Vec::new(),
+            floats: Vec::new(),
+            empty_string: "".to_string(),
+            some_string: "some".to_string(),
+        },
+    )
+}
+
+#[test]
+fn nonpresent_values() {
+    let m = flatbuffers::root::<MoreDefaults>(&[0; 4]).unwrap();
+    assert_eq!(m.ints().len(), 0);
+    assert_eq!(m.floats().len(), 0);
+    assert_eq!(m.empty_string(), "");
+    assert_eq!(m.some_string(), "some");
+}