fn test_cast_decimal256_to_numeric()

in arrow-cast/src/cast.rs [4050:4223]

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

    fn test_cast_decimal256_to_numeric() {
        let value_array: Vec<Option<i256>> = vec![
            Some(i256::from_i128(125)),
            Some(i256::from_i128(225)),
            Some(i256::from_i128(325)),
            None,
            Some(i256::from_i128(525)),
        ];
        let array = create_decimal256_array(value_array, 38, 2).unwrap();
        // u8
        generate_cast_test_case!(
            &array,
            UInt8Array,
            &DataType::UInt8,
            vec![Some(1_u8), Some(2_u8), Some(3_u8), None, Some(5_u8)]
        );
        // u16
        generate_cast_test_case!(
            &array,
            UInt16Array,
            &DataType::UInt16,
            vec![Some(1_u16), Some(2_u16), Some(3_u16), None, Some(5_u16)]
        );
        // u32
        generate_cast_test_case!(
            &array,
            UInt32Array,
            &DataType::UInt32,
            vec![Some(1_u32), Some(2_u32), Some(3_u32), None, Some(5_u32)]
        );
        // u64
        generate_cast_test_case!(
            &array,
            UInt64Array,
            &DataType::UInt64,
            vec![Some(1_u64), Some(2_u64), Some(3_u64), None, Some(5_u64)]
        );
        // i8
        generate_cast_test_case!(
            &array,
            Int8Array,
            &DataType::Int8,
            vec![Some(1_i8), Some(2_i8), Some(3_i8), None, Some(5_i8)]
        );
        // i16
        generate_cast_test_case!(
            &array,
            Int16Array,
            &DataType::Int16,
            vec![Some(1_i16), Some(2_i16), Some(3_i16), None, Some(5_i16)]
        );
        // i32
        generate_cast_test_case!(
            &array,
            Int32Array,
            &DataType::Int32,
            vec![Some(1_i32), Some(2_i32), Some(3_i32), None, Some(5_i32)]
        );
        // i64
        generate_cast_test_case!(
            &array,
            Int64Array,
            &DataType::Int64,
            vec![Some(1_i64), Some(2_i64), Some(3_i64), None, Some(5_i64)]
        );
        // f32
        generate_cast_test_case!(
            &array,
            Float32Array,
            &DataType::Float32,
            vec![
                Some(1.25_f32),
                Some(2.25_f32),
                Some(3.25_f32),
                None,
                Some(5.25_f32)
            ]
        );
        // f64
        generate_cast_test_case!(
            &array,
            Float64Array,
            &DataType::Float64,
            vec![
                Some(1.25_f64),
                Some(2.25_f64),
                Some(3.25_f64),
                None,
                Some(5.25_f64)
            ]
        );

        // overflow test: out of range of max i8
        let value_array: Vec<Option<i256>> = vec![Some(i256::from_i128(24400))];
        let array = create_decimal256_array(value_array, 38, 2).unwrap();
        let casted_array = cast_with_options(
            &array,
            &DataType::Int8,
            &CastOptions {
                safe: false,
                format_options: FormatOptions::default(),
            },
        );
        assert_eq!(
            "Cast error: value of 244 is out of range Int8".to_string(),
            casted_array.unwrap_err().to_string()
        );

        let casted_array = cast_with_options(
            &array,
            &DataType::Int8,
            &CastOptions {
                safe: true,
                format_options: FormatOptions::default(),
            },
        );
        assert!(casted_array.is_ok());
        assert!(casted_array.unwrap().is_null(0));

        // loss the precision: convert decimal to f32、f64
        // f32
        // 112345678_f32 and 112345679_f32 are same, so the 112345679_f32 will lose precision.
        let value_array: Vec<Option<i256>> = vec![
            Some(i256::from_i128(125)),
            Some(i256::from_i128(225)),
            Some(i256::from_i128(325)),
            None,
            Some(i256::from_i128(525)),
            Some(i256::from_i128(112345678)),
            Some(i256::from_i128(112345679)),
        ];
        let array = create_decimal256_array(value_array, 76, 2).unwrap();
        generate_cast_test_case!(
            &array,
            Float32Array,
            &DataType::Float32,
            vec![
                Some(1.25_f32),
                Some(2.25_f32),
                Some(3.25_f32),
                None,
                Some(5.25_f32),
                Some(1_123_456.7_f32),
                Some(1_123_456.7_f32)
            ]
        );

        // f64
        // 112345678901234568_f64 and 112345678901234560_f64 are same, so the 112345678901234568_f64 will lose precision.
        let value_array: Vec<Option<i256>> = vec![
            Some(i256::from_i128(125)),
            Some(i256::from_i128(225)),
            Some(i256::from_i128(325)),
            None,
            Some(i256::from_i128(525)),
            Some(i256::from_i128(112345678901234568)),
            Some(i256::from_i128(112345678901234560)),
        ];
        let array = create_decimal256_array(value_array, 76, 2).unwrap();
        generate_cast_test_case!(
            &array,
            Float64Array,
            &DataType::Float64,
            vec![
                Some(1.25_f64),
                Some(2.25_f64),
                Some(3.25_f64),
                None,
                Some(5.25_f64),
                Some(1_123_456_789_012_345.6_f64),
                Some(1_123_456_789_012_345.6_f64),
            ]
        );
    }