Adds changes for optional/required fields in Java code generation (#148)

code-gen-projects/input/bad/struct_with_fields/missing_required_fields.ion

@@ -0,0 +1,7 @@
+// simple struct with all valid fields
+{
+ A: "hello",
+ B: 12,
+ // C: ("foo" "bar" "baz"), // since `C` is a required field, this is an invalid struct
+ D: 10e2
+}

code-gen-projects/input/good/nested_struct/valid_optional_fields.ion

@@ -0,0 +1,9 @@
+// nested struct with some optional fields that are not provided
+{
+ A: "hello",
+ // B: 12, // since `B` is optional field, this is a valid struct
+ C: {
+    D: false,
+    E: [1, 2, 3]
+ }
+}

code-gen-projects/input/good/struct_with_fields/valid_optional_fields.ion

@@ -0,0 +1,7 @@
+// simple struct with all valid fields
+{
+ A: "hello",
+ B: 12,
+ C: ("foo" "bar" "baz"),
+ // D: 10e2, // since `D` is optional field, this is a valid struct
+}

code-gen-projects/rust/code-gen-demo/src/lib.rs

@@ -10,10 +10,28 @@ mod tests {
     use ion_rs::ReaderBuilder;
     use ion_rs::TextWriterBuilder;
     use std::fs;
+    use std::path::MAIN_SEPARATOR_STR as PATH_SEPARATOR;
     use test_generator::test_resources;
 
     include!(concat!(env!("OUT_DIR"), "/ion_generated_code.rs"));
 
+    /// Determines if the given file name is in the ROUNDTRIP_TESTS_SKIP_LIST list. This deals with platform
+    /// path separator differences from '/' separators in the path list.
+    #[inline]
+    pub fn skip_list_contains_path(file_name: &str) -> bool {
+        ROUNDTRIP_TESTS_SKIP_LIST
+            .iter()
+            // TODO construct the paths in a not so hacky way
+            .map(|p| p.replace('/', PATH_SEPARATOR))
+            .any(|p| p == file_name)
+    }
+
+    pub const ROUNDTRIP_TESTS_SKIP_LIST: &[&str] = &[
+        "../../input/good/nested_struct/valid_optional_fields.ion",
+        "../../input/good/struct_with_fields/valid_optional_fields.ion",
+        "../../input/bad/struct_with_fields/missing_required_fields.ion",
+    ];
+
     #[test]
     fn it_works() {
         let result = add(2, 2);
@@ -22,6 +40,10 @@ mod tests {
 
     #[test_resources("../../input/good/struct_with_fields/**/*.ion")]
     fn roundtrip_good_test_generated_code_structs_with_fields(file_name: &str) -> SerdeResult<()> {
+        // if file name is under the ROUNDTRIP_TESTS_SKIP_LIST then do nothing.
+        if skip_list_contains_path(&file_name) {
+            return Ok(());
+        }
         let ion_string = fs::read_to_string(file_name).unwrap();
         let mut reader = ReaderBuilder::new().build(ion_string.clone())?;
         let mut buffer = Vec::new();
@@ -43,6 +65,9 @@ mod tests {
 
     #[test_resources("../../input/bad/struct_with_fields/**/*.ion")]
     fn roundtrip_bad_test_generated_code_structs_with_fields(file_name: &str) -> SerdeResult<()> {
+        if skip_list_contains_path(&file_name) {
+            return Ok(());
+        }
         let ion_string = fs::read_to_string(file_name).unwrap();
         let mut reader = ReaderBuilder::new().build(ion_string.clone())?;
         // read given Ion value using Ion reader
@@ -55,6 +80,9 @@ mod tests {
 
     #[test_resources("../../input/good/nested_struct/**/*.ion")]
     fn roundtrip_good_test_generated_code_nested_structs(file_name: &str) -> SerdeResult<()> {
+        if skip_list_contains_path(&file_name) {
+            return Ok(());
+        }
         let ion_string = fs::read_to_string(file_name).unwrap();
         let mut reader = ReaderBuilder::new().build(ion_string.clone())?;
         let mut buffer = Vec::new();

code-gen-projects/schema/struct_with_fields.isl

@@ -4,7 +4,7 @@ type::{
  fields: {
     A: string,
     B: int,
-    C: { element: string, type: sexp },
+    C: { element: string, type: sexp, occurs: required },
     D: float,
  }
 }