fn test_avro_3814_schema_resolution_failure()

in avro/src/schema.rs [5817:5938]

• 102 lines of code
• 1 McCabe index (conditional complexity)

    fn test_avro_3814_schema_resolution_failure() -> TestResult {
        // Define a reader schema: a nested record with an optional field.
        let reader_schema = json!(
            {
                "type": "record",
                "name": "MyOuterRecord",
                "fields": [
                    {
                        "name": "inner_record",
                        "type": [
                            "null",
                            {
                                "type": "record",
                                "name": "MyRecord",
                                "fields": [
                                    {"name": "a", "type": "string"}
                                ]
                            }
                        ],
                        "default": null
                    }
                ]
            }
        );

        // Define a writer schema: a nested record with an optional field, which
        // may optionally contain an enum.
        let writer_schema = json!(
            {
                "type": "record",
                "name": "MyOuterRecord",
                "fields": [
                    {
                        "name": "inner_record",
                        "type": [
                            "null",
                            {
                                "type": "record",
                                "name": "MyRecord",
                                "fields": [
                                    {"name": "a", "type": "string"},
                                    {
                                        "name": "b",
                                        "type": [
                                            "null",
                                            {
                                                "type": "enum",
                                                "name": "MyEnum",
                                                "symbols": ["A", "B", "C"],
                                                "default": "C"
                                            }
                                        ],
                                        "default": null
                                    },
                                ]
                            }
                        ]
                    }
                ],
                "default": null
            }
        );

        // Use different structs to represent the "Reader" and the "Writer"
        // to mimic two different versions of a producer & consumer application.
        #[derive(Serialize, Deserialize, Debug)]
        struct MyInnerRecordReader {
            a: String,
        }

        #[derive(Serialize, Deserialize, Debug)]
        struct MyRecordReader {
            inner_record: Option<MyInnerRecordReader>,
        }

        #[derive(Serialize, Deserialize, Debug)]
        enum MyEnum {
            A,
            B,
            C,
        }

        #[derive(Serialize, Deserialize, Debug)]
        struct MyInnerRecordWriter {
            a: String,
            b: Option<MyEnum>,
        }

        #[derive(Serialize, Deserialize, Debug)]
        struct MyRecordWriter {
            inner_record: Option<MyInnerRecordWriter>,
        }

        let s = MyRecordWriter {
            inner_record: Some(MyInnerRecordWriter {
                a: "foo".to_string(),
                b: None,
            }),
        };

        // Serialize using the writer schema.
        let writer_schema = Schema::parse(&writer_schema)?;
        let avro_value = crate::to_value(s)?;
        assert!(
            avro_value.validate(&writer_schema),
            "value is valid for schema",
        );
        let datum = crate::to_avro_datum(&writer_schema, avro_value)?;

        // Now, attempt to deserialize using the reader schema.
        let reader_schema = Schema::parse(&reader_schema)?;
        let mut x = &datum[..];

        // Deserialization should succeed and we should be able to resolve the schema.
        let deser_value = crate::from_avro_datum(&writer_schema, &mut x, Some(&reader_schema))?;
        assert!(deser_value.validate(&reader_schema));

        // Verify that we can read a field from the record.
        let d: MyRecordReader = crate::from_value(&deser_value)?;
        assert_eq!(d.inner_record.unwrap().a, "foo".to_string());
        Ok(())
    }