math_test.go

package ajson

import (
	"errors"
	"fmt"
	"math"
	"testing"
)

func ExampleAddFunction() {
	AddFunction("array_sum", func(node *Node) (result *Node, err error) {
		if node.IsArray() {
			var (
				sum, num float64
				array    []*Node
			)
			array, err = node.GetArray()
			if err != nil {
				return nil, err
			}
			for _, child := range array {
				if !child.IsNumeric() {
					return nil, errors.New("wrong type")
				}
				num, err = child.GetNumeric()
				if err != nil {
					return
				}
				sum += num
			}
			return NumericNode("array_sum", sum), nil
		}
		return
	})
}

func ExampleAddFunction_usage() {
	json := []byte(`{"prices": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]}`)
	root, err := Unmarshal(json)
	if err != nil {
		panic(err)
	}
	result, err := Eval(root, `avg($.prices)`)
	if err != nil {
		panic(err)
	}
	fmt.Printf("Avg price: %0.1f", result.MustNumeric())
	// Output:
	// Avg price: 5.5
}

func ExampleAddConstant() {
	AddConstant("SqrtPi", NumericNode("SqrtPi", math.SqrtPi))
}

func ExampleAddConstant_using() {
	json := []byte(`{"foo": [true, null, false, 1, "bar", true, 1e3], "bar": [true, "baz", false]}`)
	result, err := JSONPath(json, `$..[?(@ == true)]`)
	if err != nil {
		panic(err)
	}
	fmt.Printf("Count of `true` values: %d", len(result))
	// Output:
	// Count of `true` values: 3
}

func ExampleAddConstant_eval() {
	json := []byte(`{"radius": 50, "position": [56.4772531, 84.9918139]}`)
	root, err := Unmarshal(json)
	if err != nil {
		panic(err)
	}
	result, err := Eval(root, `2 * $.radius * pi`)
	if err != nil {
		panic(err)
	}
	fmt.Printf("Circumference: %0.3f m.", result.MustNumeric())
	// Output:
	// Circumference: 314.159 m.
}

func ExampleAddOperation() {
	AddOperation("<>", 3, false, func(left *Node, right *Node) (node *Node, err error) {
		res, err := left.Eq(right)
		if err != nil {
			return nil, err
		}
		return BoolNode("neq", !res), nil
	})
}

func ExampleAddOperation_regex() {
	json := []byte(`[{"name":"Foo","mail":"foo@example.com"},{"name":"bar","mail":"bar@example.org"}]`)
	result, err := JSONPath(json, `$.[?(@.mail =~ '.+@example\\.com')]`)
	if err != nil {
		panic(err)
	}
	fmt.Printf("JSON: %s", result[0].Source())
	// Output:
	// JSON: {"name":"Foo","mail":"foo@example.com"}
}

type operationTest struct {
	name      string
	operation string
	left      *Node
	right     *Node
	result    *Node
	fail      bool
}

func testNumOperation(operator string, results [3]float64) []*operationTest {
	return []*operationTest{
		{name: "2" + operator + "2", operation: operator, left: NumericNode("", 2), right: NumericNode("", 2), result: NumericNode("", results[0])},
		{name: "3" + operator + "3", operation: operator, left: NumericNode("", 3), right: NumericNode("", 3), result: NumericNode("", results[1])},
		{name: "10" + operator + "3", operation: operator, left: NumericNode("", 10), right: NumericNode("", 3), result: NumericNode("", results[2])},
		{name: "X" + operator + "2", operation: operator, left: StringNode("", "X"), right: NumericNode("", 2), fail: true},
		{name: "2" + operator + "Y", operation: operator, left: NumericNode("", 2), right: StringNode("", "Y"), fail: true},
	}
}

func testBoolOperation(operator string, results [4]bool) []*operationTest {
	return []*operationTest{
		{name: "2" + operator + "2", operation: operator, left: NumericNode("", 2), right: NumericNode("", 2), result: BoolNode("", results[0])},
		{name: "3" + operator + "3", operation: operator, left: NumericNode("", 3), right: NumericNode("", 3), result: BoolNode("", results[1])},
		{name: "10" + operator + "0", operation: operator, left: NumericNode("", 10), right: NumericNode("", 0), result: BoolNode("", results[2])},
		{name: "0" + operator + "10", operation: operator, left: NumericNode("", 0), right: NumericNode("", 10), result: BoolNode("", results[3])},
		{name: "left error: " + operator, operation: operator, left: valueNode(nil, "", Numeric, "foo"), right: NumericNode("", 10), fail: true},
		{name: "right error: " + operator, operation: operator, left: NumericNode("", 10), right: valueNode(nil, "", Numeric, "foo"), fail: true},
	}
}

func testBooleanOperation(operator string, results [4]bool) []*operationTest {
	return []*operationTest{
		{name: "2" + operator + "2", operation: operator, left: NumericNode("", 2), right: NumericNode("", 2), result: BoolNode("", results[0])},
		{name: "3" + operator + "3", operation: operator, left: NumericNode("", 3), right: NumericNode("", 3), result: BoolNode("", results[1])},
		{name: "10" + operator + "0", operation: operator, left: NumericNode("", 10), right: NumericNode("", 0), result: BoolNode("", results[2])},
		{name: "0" + operator + "10", operation: operator, left: NumericNode("", 0), right: NumericNode("", 10), result: BoolNode("", results[3])},
	}
}

func TestOperations(t *testing.T) {
	tests := []*operationTest{
		{name: "0/0", operation: "/", left: NumericNode("", 0), right: NumericNode("", 0), fail: true},
		{name: "1/0", operation: "/", left: NumericNode("", 1), right: NumericNode("", 0), fail: true},
		{name: "X+Y", operation: "+", left: StringNode("", "X"), right: StringNode("", "Y"), result: StringNode("", "XY")},
	}
	tests = append(tests, testNumOperation("**", [3]float64{4, 27, 1000})...)

	tests = append(tests, testNumOperation("*", [3]float64{4, 9, 30})...)
	tests = append(tests, testNumOperation("+", [3]float64{4, 6, 13})...)
	tests = append(tests, testNumOperation("-", [3]float64{0, 0, 7})...)
	tests = append(tests, testNumOperation("/", [3]float64{1, 1, 10. / 3.})...)
	tests = append(tests, testNumOperation("%", [3]float64{0, 0, 1})...)

	tests = append(tests, testNumOperation("<<", [3]float64{8, 24, 80})...)
	tests = append(tests, testNumOperation(">>", [3]float64{0, 0, 1})...)
	tests = append(tests, testNumOperation("&", [3]float64{2, 3, 2})...)
	tests = append(tests, testNumOperation("&^", [3]float64{0, 0, 8})...)
	tests = append(tests, testNumOperation("|", [3]float64{2, 3, 11})...)
	tests = append(tests, testNumOperation("^", [3]float64{0, 0, 9})...)

	tests = append(tests, testBoolOperation("==", [4]bool{true, true, false, false})...)
	tests = append(tests, testBoolOperation("!=", [4]bool{false, false, true, true})...)
	tests = append(tests, testBoolOperation("<", [4]bool{false, false, false, true})...)
	tests = append(tests, testBoolOperation("<=", [4]bool{true, true, false, true})...)
	tests = append(tests, testBoolOperation(">", [4]bool{false, false, true, false})...)
	tests = append(tests, testBoolOperation(">=", [4]bool{true, true, true, false})...)

	tests = append(tests, testBooleanOperation("&&", [4]bool{true, true, false, false})...)
	tests = append(tests, testBooleanOperation("||", [4]bool{true, true, true, true})...)

	_e := valueNode(nil, "", Numeric, "foo")
	_t := NumericNode("", 1)
	_f := NumericNode("", 0)
	_false := BoolNode("", false)
	_true := BoolNode("", true)
	tests = append(
		tests,
		&operationTest{name: "error && true", operation: "&&", left: _e, right: _t, fail: true},
		&operationTest{name: "error && error", operation: "&&", left: _e, right: _e, fail: true},
		&operationTest{name: "error && false", operation: "&&", left: _e, right: _f, fail: true},
		&operationTest{name: "false && error", operation: "&&", left: _f, right: _e, result: _false},
		&operationTest{name: "true && error", operation: "&&", left: _t, right: _e, fail: true},
		&operationTest{
			name:      "[] && {} == false",
			operation: "&&",
			left:      ArrayNode("", []*Node{}),
			right:     ObjectNode("", map[string]*Node{}),
			result:    _false,
		},
		&operationTest{
			name:      "{} || [] == false",
			operation: "||",
			left:      ObjectNode("", map[string]*Node{}),
			right:     ArrayNode("", []*Node{}),
			result:    _false,
		},
		&operationTest{
			name:      `{"foo":"bar"} || [1] == true`,
			operation: "&&",
			left:      ObjectNode("", map[string]*Node{"foo": StringNode("foo", "bar")}),
			right:     ArrayNode("", []*Node{NumericNode("0", 1)}),
			result:    _true,
		},

		&operationTest{name: "error || true", operation: "||", left: _e, right: _t, fail: true},
		&operationTest{name: "error || error", operation: "||", left: _e, right: _e, fail: true},
		&operationTest{name: "error || false", operation: "||", left: _e, right: _f, fail: true},
		&operationTest{name: "false || error", operation: "||", left: _f, right: _e, fail: true},
		&operationTest{name: "true || error", operation: "||", left: _t, right: _e, result: _true},

		&operationTest{name: "regexp true", operation: "=~", left: StringNode("", `123`), right: StringNode("", `\d+`), result: _true},
		&operationTest{name: "regexp false", operation: "=~", left: StringNode("", `1 2 3`), right: StringNode("", `^\d+$`), result: _false},
		&operationTest{name: "regexp pattern error", operation: "=~", left: StringNode("", `2`), right: StringNode("", `\2`), fail: true},
		&operationTest{name: "regexp error 1", operation: "=~", left: _f, right: StringNode("", `123`), fail: true},
		&operationTest{name: "regexp error 2", operation: "=~", left: StringNode("", `\d+`), right: _f, fail: true},
	)

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			result, err := operations[test.operation](test.left, test.right)
			if test.fail {
				if err == nil {
					t.Error("Expected error: nil given")
				}
			} else if err != nil {
				t.Errorf("Unexpected error: %s", err.Error())
			} else if ok, err := result.Eq(test.result); !ok {
				if err != nil {
					t.Errorf("Unexpected error on comparation: %s", err.Error())
				}
				t.Errorf("Wrong value: %v != %v", result.value.Load(), test.result.value.Load())
			}
		})
	}
}

func TestAddConstant(t *testing.T) {
	name := "new_constant_name"
	if _, ok := constants[name]; ok {
		t.Error("test constant already exists")
	}
	AddConstant(name, NumericNode(name, 3.14))
	if _, ok := constants[name]; !ok {
		t.Error("test constant was not added")
	}
}

func TestAddOperation(t *testing.T) {
	name := "_one_to_rule_them_all_"
	if _, ok := operations[name]; ok {
		t.Error("test operation already exists")
		return
	}
	AddOperation(name, 1, true, func(left *Node, right *Node) (result *Node, err error) {
		return NumericNode("example", 1), nil
	})
	if _, ok := operations[name]; !ok {
		t.Error("test operation was not added")
		return
	}
	result, err := Eval(NullNode(""), `@ _one_to_rule_them_all_ 100500`)
	if err != nil {
		t.Errorf("Unexpected error: %s", err.Error())
		return
	}
	if ok, err := result.Eq(NumericNode("", 1)); err != nil {
		t.Errorf("Unexpected error: %s", err.Error())
	} else if !ok {
		t.Errorf("Should be one")
	}
}

func TestAddFunction(t *testing.T) {
	name := "new_function_name"
	if _, ok := functions[name]; ok {
		t.Error("test constant already exists")
	}
	AddFunction(name, func(node *Node) (result *Node, err error) {
		return NumericNode("example", 2), nil
	})
	if _, ok := functions[name]; !ok {
		t.Error("test function was not added")
	}
}

func TestFunctions(t *testing.T) {
	var (
		expectedRandomFloat = 0.912
		expectedRandomInt   = 45
	)
	randFunc = func() float64 {
		return expectedRandomFloat
	}
	randIntFunc = func(n int) int {
		return expectedRandomInt
	}
	tests := []struct {
		name   string
		fname  string
		value  float64
		result interface{}
	}{
		{name: "abs 1", fname: "abs", value: float64(-100), result: 100},
		{name: "abs 2", fname: "abs", value: float64(100), result: 100},
		{name: "abs 3", fname: "abs", value: float64(0), result: 0},
		{name: "acos 1", fname: "acos", value: float64(0.5), result: math.Acos(0.5)},
		{name: "acosh 1", fname: "acosh", value: float64(100), result: math.Acosh(100)},
		{name: "asin 1", fname: "asin", value: float64(0.5), result: math.Asin(0.5)},
		{name: "asinh 1", fname: "asinh", value: float64(100), result: math.Asinh(100)},
		{name: "atan 1", fname: "atan", value: float64(100), result: math.Atan(100)},
		{name: "atanh 1", fname: "atanh", value: float64(0.5), result: math.Atanh(0.5)},
		{name: "cbrt 1", fname: "cbrt", value: float64(100), result: math.Cbrt(100)},
		{name: "ceil 1", fname: "ceil", value: float64(100), result: math.Ceil(100)},
		{name: "cos 1", fname: "cos", value: float64(100), result: math.Cos(100)},
		{name: "cosh 1", fname: "cosh", value: float64(100), result: math.Cosh(100)},
		{name: "erf 1", fname: "erf", value: float64(100), result: math.Erf(100)},
		{name: "erfc 1", fname: "erfc", value: float64(100), result: math.Erfc(100)},
		{name: "erfcinv 1", fname: "erfcinv", value: float64(0.5), result: math.Erfcinv(0.5)},
		{name: "erfinv 1", fname: "erfinv", value: float64(0.5), result: math.Erfinv(0.5)},
		{name: "exp 1", fname: "exp", value: float64(100), result: math.Exp(100)},
		{name: "exp2 1", fname: "exp2", value: float64(100), result: math.Exp2(100)},
		{name: "expm1 1", fname: "expm1", value: float64(100), result: math.Expm1(100)},
		{name: "floor 1", fname: "floor", value: float64(0), result: math.Floor(0)},
		{name: "floor 2", fname: "floor", value: float64(0.1), result: math.Floor(0.1)},
		{name: "floor 3", fname: "floor", value: float64(0.5), result: math.Floor(0.5)},
		{name: "floor 4", fname: "floor", value: float64(0.9), result: math.Floor(0.9)},
		{name: "floor 5", fname: "floor", value: float64(100), result: math.Floor(100)},
		{name: "gamma 1", fname: "gamma", value: float64(100), result: math.Gamma(100)},
		{name: "j0 1", fname: "j0", value: float64(100), result: math.J0(100)},
		{name: "j1 1", fname: "j1", value: float64(100), result: math.J1(100)},
		{name: "log 1", fname: "log", value: float64(100), result: math.Log(100)},
		{name: "log10 1", fname: "log10", value: float64(100), result: math.Log10(100)},
		{name: "log1p 1", fname: "log1p", value: float64(100), result: math.Log1p(100)},
		{name: "log2 1", fname: "log2", value: float64(100), result: math.Log2(100)},
		{name: "logb 1", fname: "logb", value: float64(100), result: math.Logb(100)},
		{name: "round 1", fname: "round", value: float64(0), result: math.Round(0)},
		{name: "round 2", fname: "round", value: float64(0.1), result: math.Round(0.1)},
		{name: "round 3", fname: "round", value: float64(0.5), result: math.Round(0.5)},
		{name: "round 4", fname: "round", value: float64(0.9), result: math.Round(0.9)},
		{name: "round 5", fname: "round", value: float64(100), result: math.Round(100)},
		{name: "roundtoeven 1", fname: "roundtoeven", value: float64(0), result: math.RoundToEven(0)},
		{name: "roundtoeven 2", fname: "roundtoeven", value: float64(0.5), result: math.RoundToEven(0.5)},
		{name: "roundtoeven 3", fname: "roundtoeven", value: float64(0.1), result: math.RoundToEven(0.1)},
		{name: "roundtoeven 4", fname: "roundtoeven", value: float64(0.9), result: math.RoundToEven(0.9)},
		{name: "roundtoeven 5", fname: "roundtoeven", value: float64(1), result: math.RoundToEven(1)},
		{name: "sin 1", fname: "sin", value: float64(100), result: math.Sin(100)},
		{name: "sinh 1", fname: "sinh", value: float64(100), result: math.Sinh(100)},
		{name: "sqrt 1", fname: "sqrt", value: float64(100), result: math.Sqrt(100)},
		{name: "tan 1", fname: "tan", value: float64(100), result: math.Tan(100)},
		{name: "tanh 1", fname: "tanh", value: float64(100), result: math.Tanh(100)},
		{name: "trunc 1", fname: "trunc", value: float64(100), result: math.Trunc(100)},
		{name: "y0 1", fname: "y0", value: float64(100), result: math.Y0(100)},
		{name: "y1 1", fname: "y1", value: float64(100), result: math.Y1(100)},

		{name: "pow10", fname: "pow10", value: float64(10), result: math.Pow10(10)},
		{name: "factorial", fname: "factorial", value: float64(10), result: 3628800},

		{name: "not_1", fname: "not", value: float64(1), result: false},
		{name: "not_0", fname: "not", value: float64(0), result: true},

		{name: "rand 50", fname: "rand", value: 50, result: expectedRandomFloat * 50},
		{name: "randint 50", fname: "randint", value: 50, result: expectedRandomInt},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			node := NumericNode(test.name, test.value)
			var expected *Node
			switch test.result.(type) {
			case int:
				expected = NumericNode(test.fname, float64(test.result.(int)))
			case float64:
				expected = NumericNode(test.fname, test.result.(float64))
			case bool:
				expected = BoolNode(test.fname, test.result.(bool))
			default:
				panic("wrong type")
			}
			result, err := functions[test.fname](node)
			if err != nil {
				t.Errorf("Unexpected error: %s", err.Error())
			} else if ok, err := result.Eq(expected); !ok {
				if err != nil {
					t.Errorf("Unexpected error on comparation: %s", err.Error())
				}
				t.Errorf("Wrong value: %v != %v", result.value.Load(), expected.value.Load())
			}
		})
	}
}

func TestFunctions2(t *testing.T) {
	key := StringNode("", "value")
	parent := ObjectNode("test", map[string]*Node{
		"t": key,
		"y": NumericNode("", 2),
	})
	object := ObjectNode("test", map[string]*Node{
		"q": NumericNode("", 1),
		"w": NumericNode("", 2),
		"e": NumericNode("", 3),
		"r": parent,
	})

	_e := valueNode(nil, "", Numeric, "foo")
	_s := valueNode(nil, "", String, true)
	tests := []struct {
		name   string
		fname  string
		value  *Node
		result *Node
		fail   bool
	}{
		{name: "pow10 error", fname: "pow10", value: _e, fail: true},
		{name: "factorial error", fname: "factorial", value: _e, fail: true},
		{name: "abs error 1", fname: "abs", value: _e, fail: true},
		{name: "abs error 2", fname: "abs", value: StringNode("", ""), fail: true},

		{name: "length array", fname: "length", value: ArrayNode("test", []*Node{
			valueNode(nil, "", Numeric, "foo"),
			valueNode(nil, "", Numeric, "foo"),
			valueNode(nil, "", Numeric, "foo"),
		}), result: NumericNode("", 3)},
		{name: "length blank array", fname: "length", value: ArrayNode("test", []*Node{}), result: NumericNode("", 0)},
		{name: "length object", fname: "length", value: ObjectNode("test", map[string]*Node{
			"foo": NumericNode("foo", 1),
			"bar": NumericNode("bar", 1),
		}), result: NumericNode("", 1)},
		{name: "length string", fname: "length", value: StringNode("", "foo_bar"), result: NumericNode("", 7)},
		{name: "length string error", fname: "length", value: _s, fail: true},
		{name: "length numeric", fname: "length", value: NumericNode("", 123), result: NumericNode("", 1)},
		{name: "length bool", fname: "length", value: BoolNode("", false), result: NumericNode("", 1)},
		{name: "length null", fname: "length", value: NullNode(""), result: NumericNode("", 1)},
		{name: "length nil", fname: "length", value: nil, result: NumericNode("", 0)},

		{name: "size array", fname: "size", value: ArrayNode("test", []*Node{
			valueNode(nil, "", Numeric, "foo"),
			valueNode(nil, "", Numeric, "foo"),
			valueNode(nil, "", Numeric, "foo"),
		}), result: NumericNode("", 3)},
		{name: "size blank array", fname: "size", value: ArrayNode("test", []*Node{}), result: NumericNode("", 0)},
		{name: "size object", fname: "size", value: ObjectNode("test", map[string]*Node{
			"foo": NumericNode("foo", 1),
			"bar": NumericNode("bar", 1),
		}), result: NumericNode("", 2)},
		{name: "size string", fname: "size", value: StringNode("", "foo_bar"), result: NumericNode("", 0)},
		{name: "size numeric", fname: "size", value: NumericNode("", 123), result: NumericNode("", 0)},
		{name: "size bool", fname: "size", value: BoolNode("", false), result: NumericNode("", 0)},
		{name: "size null", fname: "size", value: NullNode(""), result: NumericNode("", 0)},
		{name: "size nil", fname: "size", value: nil, result: NumericNode("", 0)},

		{name: "avg error 1", fname: "avg", value: ArrayNode("test", []*Node{
			valueNode(nil, "", Numeric, "foo"),
			valueNode(nil, "", Numeric, "foo"),
			valueNode(nil, "", Numeric, "foo"),
		}), fail: true},
		{name: "avg error 2", fname: "avg", value: _e, fail: true},
		{name: "avg array 1", fname: "avg", value: ArrayNode("test", []*Node{
			NumericNode("", 1),
			NumericNode("", 1),
			NumericNode("", 1),
			NumericNode("", 1),
		}), result: NumericNode("", 1)},
		{name: "avg array 2", fname: "avg", value: ArrayNode("test", []*Node{
			NumericNode("", 1),
			NumericNode("", 2),
			NumericNode("", 3),
		}), result: NumericNode("", 2)},
		{name: "avg object", fname: "avg", value: ObjectNode("test", map[string]*Node{
			"q": NumericNode("", 1),
			"w": NumericNode("", 2),
			"e": NumericNode("", 3),
		}), result: NumericNode("", 2)},
		{name: "avg array blank", fname: "avg", value: ArrayNode("test", []*Node{}), result: NumericNode("", 0)},
		{name: "avg nil", fname: "avg", value: nil, result: NullNode("")},
		{name: "avg one", fname: "avg", value: NumericNode("", 123), result: NumericNode("", 123)},

		{name: "b64encode_std_padding multiple of 3", fname: "b64encode", value: StringNode("", "Short string"), result: StringNode("", "U2hvcnQgc3RyaW5n")},
		{name: "b64encode_std_padding remainder 2", fname: "b64encode", value: StringNode("", "A test string"), result: StringNode("", "QSB0ZXN0IHN0cmluZw==")},
		{name: "b64encode_std_padding remainder 1", fname: "b64encode", value: StringNode("", "A test string."), result: StringNode("", "QSB0ZXN0IHN0cmluZy4=")},
		{name: "b64encode_std_padding nil", fname: "b64encode", value: nil, result: NullNode("")},

		{name: "b64encode_no_padding multiple of 3", fname: "b64encoden", value: StringNode("", "Short string"), result: StringNode("", "U2hvcnQgc3RyaW5n")},
		{name: "b64encode_no_padding remainder 2", fname: "b64encoden", value: StringNode("", "A test string"), result: StringNode("", "QSB0ZXN0IHN0cmluZw")},
		{name: "b64encode_no_padding remainder 1", fname: "b64encoden", value: StringNode("", "A test string."), result: StringNode("", "QSB0ZXN0IHN0cmluZy4")},
		{name: "b64encode_no_padding nil", fname: "b64encoden", value: nil, result: NullNode("")},

		{name: "b64decode with padding multiple of 3", fname: "b64decode", value: StringNode("", "U2hvcnQgc3RyaW5n"), result: StringNode("", "Short string")},
		{name: "b64decode with padding remainder 2", fname: "b64decode", value: StringNode("", "QSB0ZXN0IHN0cmluZw=="), result: StringNode("", "A test string")},
		{name: "b64decode with padding remainder 1", fname: "b64decode", value: StringNode("", "QSB0ZXN0IHN0cmluZy4="), result: StringNode("", "A test string.")},
		{name: "b64decode nil", fname: "b64decode", value: nil, result: NullNode("")},

		{name: "b64decode without padding multiple of 3", fname: "b64decode", value: StringNode("", "U2hvcnQgc3RyaW5n"), result: StringNode("", "Short string")},
		{name: "b64decode without padding remainder 2", fname: "b64decode", value: StringNode("", "QSB0ZXN0IHN0cmluZw"), result: StringNode("", "A test string")},
		{name: "b64decode without padding remainder 1", fname: "b64decode", value: StringNode("", "QSB0ZXN0IHN0cmluZy4"), result: StringNode("", "A test string.")},

		{name: "b64decode with padding wrong characters", fname: "b64decode", value: StringNode("", "!!!!Non-ASCII-Chars!!!!"), fail: true},
		{name: "b64decode with padding wrong length", fname: "b64decode", value: StringNode("", "QSB0ZXN0IHN0cmluZwU=="), fail: true},

		{name: "sum error 1", fname: "sum", value: ArrayNode("test", []*Node{
			valueNode(nil, "", Numeric, "foo"),
			valueNode(nil, "", Numeric, "foo"),
			valueNode(nil, "", Numeric, "foo"),
		}), fail: true},
		{name: "sum error 2", fname: "sum", value: _e, fail: true},
		{name: "sum array 1", fname: "sum", value: ArrayNode("test", []*Node{
			NumericNode("", 1),
			NumericNode("", 1),
			NumericNode("", 1),
			NumericNode("", 1),
		}), result: NumericNode("", 4)},
		{name: "sum array 2", fname: "sum", value: ArrayNode("test", []*Node{
			NumericNode("", 1),
			NumericNode("", 2),
			NumericNode("", 3),
		}), result: NumericNode("", 6)},
		{name: "sum object", fname: "sum", value: ObjectNode("test", map[string]*Node{
			"q": NumericNode("", 1),
			"w": NumericNode("", 2),
			"e": NumericNode("", 3),
		}), result: NumericNode("", 6)},
		{name: "sum array blank", fname: "sum", value: ArrayNode("test", []*Node{}), result: NumericNode("", 0)},
		{name: "sum nil", fname: "sum", value: nil, result: NullNode("")},
		{name: "sum one", fname: "sum", value: NumericNode("", 123), result: NumericNode("", 123)},

		{name: "rand", fname: "rand", value: StringNode("test", "test"), fail: true},
		{name: "randint", fname: "randint", value: StringNode("test", "test"), fail: true},

		{name: "last: string", fname: "last", value: StringNode("", ""), result: NullNode(""), fail: false},
		{name: "last: empty", fname: "last", value: ArrayNode("", []*Node{}), result: NullNode(""), fail: false},
		{name: "last: one", fname: "last", value: ArrayNode("", []*Node{StringNode("", "value")}), result: StringNode("", "value"), fail: false},
		{name: "last: several", fname: "last", value: ArrayNode("", []*Node{
			StringNode("", "1"),
			StringNode("", "2"),
			StringNode("", "3"),
		}), result: StringNode("", "3"), fail: false},
		{name: "last: object", fname: "last", value: ObjectNode("test", map[string]*Node{
			"q": NumericNode("", 1),
			"w": NumericNode("", 2),
			"e": NumericNode("", 3),
		}), result: NullNode(""), fail: false},
		{name: "last nil", fname: "last", value: nil, result: NullNode("")},

		{name: "first: string", fname: "first", value: StringNode("", ""), result: NullNode(""), fail: false},
		{name: "first: empty", fname: "first", value: ArrayNode("", []*Node{}), result: NullNode(""), fail: false},
		{name: "first: one", fname: "first", value: ArrayNode("", []*Node{StringNode("", "value")}), result: StringNode("", "value"), fail: false},
		{name: "first: several", fname: "first", value: ArrayNode("", []*Node{
			StringNode("", "1"),
			StringNode("", "2"),
			StringNode("", "3"),
		}), result: StringNode("", "1"), fail: false},
		{name: "first: object", fname: "first", value: ObjectNode("test", map[string]*Node{
			"q": NumericNode("", 1),
			"w": NumericNode("", 2),
			"e": NumericNode("", 3),
		}), result: NullNode(""), fail: false},
		{name: "first nil", fname: "first", value: nil, result: NullNode("")},

		{name: "parent", fname: "parent", value: key, result: parent, fail: false},
		{name: "parent: none", fname: "parent", value: object, result: NullNode(""), fail: false},
		{name: "root", fname: "root", value: key, result: object, fail: false},
		{name: "root: self", fname: "root", value: object, result: object, fail: false},
		{name: "key", fname: "key", value: key, result: StringNode("", "t"), fail: false},
		{name: "key: none", fname: "key", value: StringNode("", "value"), result: NullNode(""), fail: false},
		{name: "key nil", fname: "key", value: nil, result: NullNode("")},

		{name: "is_null nil", fname: "is_null", value: nil, result: NullNode("")},
		{name: "is_null null", fname: "is_null", value: NullNode(""), result: BoolNode("", true)},
		{name: "is_null str", fname: "is_null", value: StringNode("", ""), result: BoolNode("", false)},
		{name: "is_numeric nil", fname: "is_numeric", value: nil, result: NullNode("")},
		{name: "is_numeric null", fname: "is_numeric", value: NullNode(""), result: BoolNode("", false)},
		{name: "is_numeric int", fname: "is_numeric", value: NumericNode("", -123), result: BoolNode("", true)},
		{name: "is_numeric uint", fname: "is_numeric", value: NumericNode("", 123), result: BoolNode("", true)},
		{name: "is_numeric float", fname: "is_numeric", value: NumericNode("", -12.34), result: BoolNode("", true)},
		{name: "is_numeric string", fname: "is_numeric", value: StringNode("", ""), result: BoolNode("", false)},
		{name: "is_numeric bool", fname: "is_numeric", value: BoolNode("", true), result: BoolNode("", false)},
		{name: "is_numeric array", fname: "is_numeric", value: ArrayNode("", nil), result: BoolNode("", false)},
		{name: "is_numeric object", fname: "is_numeric", value: ObjectNode("", nil), result: BoolNode("", false)},
		{name: "is_int nil", fname: "is_int", value: nil, result: NullNode("")},
		{name: "is_int null", fname: "is_int", value: NullNode(""), result: BoolNode("", false)},
		{name: "is_int int", fname: "is_int", value: NumericNode("", -123), result: BoolNode("", true)},
		{name: "is_int uint", fname: "is_int", value: NumericNode("", 123), result: BoolNode("", true)},
		{name: "is_int float", fname: "is_int", value: NumericNode("", -12.34), result: BoolNode("", false)},
		{name: "is_int string", fname: "is_int", value: StringNode("", ""), result: BoolNode("", false)},
		{name: "is_int bool", fname: "is_int", value: BoolNode("", true), result: BoolNode("", false)},
		{name: "is_int array", fname: "is_int", value: ArrayNode("", nil), result: BoolNode("", false)},
		{name: "is_int object", fname: "is_int", value: ObjectNode("", nil), result: BoolNode("", false)},
		{name: "is_uint nil", fname: "is_uint", value: nil, result: NullNode("")},
		{name: "is_uint null", fname: "is_uint", value: NullNode(""), result: BoolNode("", false)},
		{name: "is_uint int", fname: "is_uint", value: NumericNode("", -123), result: BoolNode("", false)},
		{name: "is_uint uint", fname: "is_uint", value: NumericNode("", 123), result: BoolNode("", true)},
		{name: "is_uint float", fname: "is_uint", value: NumericNode("", -12.34), result: BoolNode("", false)},
		{name: "is_uint string", fname: "is_uint", value: StringNode("", ""), result: BoolNode("", false)},
		{name: "is_uint bool", fname: "is_uint", value: BoolNode("", true), result: BoolNode("", false)},
		{name: "is_uint array", fname: "is_uint", value: ArrayNode("", nil), result: BoolNode("", false)},
		{name: "is_uint object", fname: "is_uint", value: ObjectNode("", nil), result: BoolNode("", false)},
		{name: "is_float nil", fname: "is_float", value: nil, result: NullNode("")},
		{name: "is_float null", fname: "is_float", value: NullNode(""), result: BoolNode("", false)},
		{name: "is_float int", fname: "is_float", value: NumericNode("", -123), result: BoolNode("", false)},
		{name: "is_float uint", fname: "is_float", value: NumericNode("", 123), result: BoolNode("", false)},
		{name: "is_float float", fname: "is_float", value: NumericNode("", -12.34), result: BoolNode("", true)},
		{name: "is_float string", fname: "is_float", value: StringNode("", ""), result: BoolNode("", false)},
		{name: "is_float bool", fname: "is_float", value: BoolNode("", true), result: BoolNode("", false)},
		{name: "is_float array", fname: "is_float", value: ArrayNode("", nil), result: BoolNode("", false)},
		{name: "is_float object", fname: "is_float", value: ObjectNode("", nil), result: BoolNode("", false)},
		{name: "is_string nil", fname: "is_string", value: nil, result: NullNode("")},
		{name: "is_string null", fname: "is_string", value: NullNode(""), result: BoolNode("", false)},
		{name: "is_string int", fname: "is_string", value: NumericNode("", -123), result: BoolNode("", false)},
		{name: "is_string uint", fname: "is_string", value: NumericNode("", 123), result: BoolNode("", false)},
		{name: "is_string float", fname: "is_string", value: NumericNode("", -12.34), result: BoolNode("", false)},
		{name: "is_string string", fname: "is_string", value: StringNode("", ""), result: BoolNode("", true)},
		{name: "is_string bool", fname: "is_string", value: BoolNode("", true), result: BoolNode("", false)},
		{name: "is_string array", fname: "is_string", value: ArrayNode("", nil), result: BoolNode("", false)},
		{name: "is_string object", fname: "is_string", value: ObjectNode("", nil), result: BoolNode("", false)},
		{name: "is_bool nil", fname: "is_bool", value: nil, result: NullNode("")},
		{name: "is_bool null", fname: "is_bool", value: NullNode(""), result: BoolNode("", false)},
		{name: "is_bool int", fname: "is_bool", value: NumericNode("", -123), result: BoolNode("", false)},
		{name: "is_bool uint", fname: "is_bool", value: NumericNode("", 123), result: BoolNode("", false)},
		{name: "is_bool float", fname: "is_bool", value: NumericNode("", -12.34), result: BoolNode("", false)},
		{name: "is_bool string", fname: "is_bool", value: StringNode("", ""), result: BoolNode("", false)},
		{name: "is_bool bool", fname: "is_bool", value: BoolNode("", true), result: BoolNode("", true)},
		{name: "is_bool array", fname: "is_bool", value: ArrayNode("", nil), result: BoolNode("", false)},
		{name: "is_bool object", fname: "is_bool", value: ObjectNode("", nil), result: BoolNode("", false)},
		{name: "is_array nil", fname: "is_array", value: nil, result: NullNode("")},
		{name: "is_array null", fname: "is_array", value: NullNode(""), result: BoolNode("", false)},
		{name: "is_array int", fname: "is_array", value: NumericNode("", -123), result: BoolNode("", false)},
		{name: "is_array uint", fname: "is_array", value: NumericNode("", 123), result: BoolNode("", false)},
		{name: "is_array float", fname: "is_array", value: NumericNode("", -12.34), result: BoolNode("", false)},
		{name: "is_array string", fname: "is_array", value: StringNode("", ""), result: BoolNode("", false)},
		{name: "is_array bool", fname: "is_array", value: BoolNode("", true), result: BoolNode("", false)},
		{name: "is_array array", fname: "is_array", value: ArrayNode("", nil), result: BoolNode("", true)},
		{name: "is_array object", fname: "is_array", value: ObjectNode("", nil), result: BoolNode("", false)},
		{name: "is_object nil", fname: "is_object", value: nil, result: NullNode("")},
		{name: "is_object null", fname: "is_object", value: NullNode(""), result: BoolNode("", false)},
		{name: "is_object int", fname: "is_object", value: NumericNode("", -123), result: BoolNode("", false)},
		{name: "is_object uint", fname: "is_object", value: NumericNode("", 123), result: BoolNode("", false)},
		{name: "is_object float", fname: "is_object", value: NumericNode("", -12.34), result: BoolNode("", false)},
		{name: "is_object string", fname: "is_object", value: StringNode("", ""), result: BoolNode("", false)},
		{name: "is_object bool", fname: "is_object", value: BoolNode("", true), result: BoolNode("", false)},
		{name: "is_object array", fname: "is_object", value: ArrayNode("", nil), result: BoolNode("", false)},
		{name: "is_object object", fname: "is_object", value: ObjectNode("", nil), result: BoolNode("", true)},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			result, err := functions[test.fname](test.value)
			if test.fail {
				if err == nil {
					t.Error("Expected error: nil given")
				}
			} else if err != nil {
				t.Errorf("Unexpected error: %s", err.Error())
			} else if ok, err := result.Eq(test.result); !ok {
				if err != nil {
					t.Errorf("Unexpected error on comparation: %s", err.Error())
				}
				t.Errorf("Wrong value: %v != %v", result.value.Load(), test.result.value.Load())
			}
		})
	}
}

func TestConstants(t *testing.T) {
	tests := []struct {
		name     string
		expected *Node
	}{
		{name: "e", expected: NumericNode("e", float64(math.E))},
		{name: "pi", expected: NumericNode("pi", float64(math.Pi))},
		{name: "phi", expected: NumericNode("phi", float64(math.Phi))},

		{name: "sqrt2", expected: NumericNode("sqrt2", float64(math.Sqrt2))},
		{name: "sqrte", expected: NumericNode("sqrte", float64(math.SqrtE))},
		{name: "sqrtpi", expected: NumericNode("sqrtpi", float64(math.SqrtPi))},
		{name: "sqrtphi", expected: NumericNode("sqrtphi", float64(math.SqrtPhi))},

		{name: "ln2", expected: NumericNode("ln2", float64(math.Ln2))},
		{name: "log2e", expected: NumericNode("log2e", float64(math.Log2E))},
		{name: "ln10", expected: NumericNode("ln10", float64(math.Ln10))},
		{name: "log10e", expected: NumericNode("log10e", float64(math.Log10E))},

		{name: "true", expected: BoolNode("true", true)},
		{name: "false", expected: BoolNode("false", false)},
		{name: "null", expected: NullNode("null")},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			result := constants[test.name]
			if ok, err := result.Eq(test.expected); !ok {
				if err != nil {
					t.Errorf("Unexpected error on comparation: %s", err.Error())
				}
				t.Errorf("Wrong value: %v != %v", result.value.Load(), test.expected.value.Load())
			}
		})
	}
}