github.com/apache/arrow/go/v14@v14.0.2/arrow/compute/exec/kernel_test.go

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//go:build go1.18

package exec_test

import (
	"fmt"
	"testing"

	"github.com/apache/arrow/go/v14/arrow"
	"github.com/apache/arrow/go/v14/arrow/array"
	"github.com/apache/arrow/go/v14/arrow/compute"
	"github.com/apache/arrow/go/v14/arrow/compute/exec"
	"github.com/apache/arrow/go/v14/arrow/memory"
	"github.com/apache/arrow/go/v14/arrow/scalar"
	"github.com/stretchr/testify/assert"
)

func TestTypeMatcherSameTypeID(t *testing.T) {
	matcher := exec.SameTypeID(arrow.DECIMAL128)
	assert.True(t, matcher.Matches(&arrow.Decimal128Type{Precision: 12, Scale: 2}))
	assert.False(t, matcher.Matches(arrow.PrimitiveTypes.Int8))

	assert.Equal(t, "Type::DECIMAL128", matcher.String())

	assert.True(t, matcher.Equals(matcher))
	assert.True(t, matcher.Equals(exec.SameTypeID(arrow.DECIMAL)))
	assert.False(t, matcher.Equals(exec.SameTypeID(arrow.TIMESTAMP)))
	assert.False(t, matcher.Equals(exec.Time32TypeUnit(arrow.Microsecond)))
}

func TestTypeMatcherTimestampTypeUnit(t *testing.T) {
	matcher := exec.TimestampTypeUnit(arrow.Millisecond)
	matcher2 := exec.Time32TypeUnit(arrow.Millisecond)
	matcher3 := exec.Time64TypeUnit(arrow.Microsecond)
	matcher4 := exec.DurationTypeUnit(arrow.Microsecond)

	assert.True(t, matcher.Matches(arrow.FixedWidthTypes.Timestamp_ms))
	assert.True(t, matcher.Matches(&arrow.TimestampType{Unit: arrow.Millisecond, TimeZone: "utc"}))
	assert.False(t, matcher.Matches(arrow.FixedWidthTypes.Timestamp_s))
	assert.False(t, matcher.Matches(arrow.FixedWidthTypes.Time32ms))
	assert.True(t, matcher2.Matches(arrow.FixedWidthTypes.Time32ms))

	assert.True(t, matcher3.Matches(arrow.FixedWidthTypes.Time64us))
	assert.False(t, matcher3.Matches(arrow.FixedWidthTypes.Time64ns))
	assert.True(t, matcher4.Matches(arrow.FixedWidthTypes.Duration_us))
	assert.False(t, matcher4.Matches(arrow.FixedWidthTypes.Duration_ms))

	// check String() representation
	assert.Equal(t, "timestamp(s)", exec.TimestampTypeUnit(arrow.Second).String())
	assert.Equal(t, "timestamp(ms)", exec.TimestampTypeUnit(arrow.Millisecond).String())
	assert.Equal(t, "timestamp(us)", exec.TimestampTypeUnit(arrow.Microsecond).String())
	assert.Equal(t, "timestamp(ns)", exec.TimestampTypeUnit(arrow.Nanosecond).String())

	// equals implementation
	assert.True(t, matcher.Equals(matcher))
	assert.True(t, matcher.Equals(exec.TimestampTypeUnit(arrow.Millisecond)))
	assert.False(t, matcher.Equals(exec.TimestampTypeUnit(arrow.Microsecond)))
	assert.False(t, matcher.Equals(exec.Time32TypeUnit(arrow.Millisecond)))
	assert.False(t, matcher3.Equals(matcher2))
	assert.False(t, matcher4.Equals(matcher3))
	assert.True(t, matcher4.Equals(exec.DurationTypeUnit(arrow.Microsecond)))
	assert.False(t, matcher.Equals(exec.SameTypeID(arrow.TIMESTAMP)))
}

func TestIntegerMatcher(t *testing.T) {
	match := exec.Integer()

	assert.Equal(t, "integer", match.String())
	assert.True(t, match.Matches(arrow.PrimitiveTypes.Int8))
	assert.True(t, match.Matches(arrow.PrimitiveTypes.Uint64))
	assert.True(t, match.Equals(exec.Integer()))
	assert.False(t, match.Equals(exec.BinaryLike()))
}

func TestBinaryLikeMatcher(t *testing.T) {
	match := exec.BinaryLike()

	assert.Equal(t, "binary-like", match.String())
	assert.True(t, match.Matches(arrow.BinaryTypes.String))
	assert.True(t, match.Matches(arrow.BinaryTypes.Binary))
	assert.False(t, match.Matches(arrow.BinaryTypes.LargeString))
	assert.False(t, match.Matches(arrow.BinaryTypes.LargeBinary))
	assert.False(t, match.Equals(exec.LargeBinaryLike()))
	assert.True(t, match.Equals(exec.BinaryLike()))
}

func TestLargeBinaryLikeMatcher(t *testing.T) {
	match := exec.LargeBinaryLike()

	assert.Equal(t, "large-binary-like", match.String())
	assert.False(t, match.Matches(arrow.BinaryTypes.String))
	assert.False(t, match.Matches(arrow.BinaryTypes.Binary))
	assert.True(t, match.Matches(arrow.BinaryTypes.LargeString))
	assert.True(t, match.Matches(arrow.BinaryTypes.LargeBinary))
	assert.True(t, match.Equals(exec.LargeBinaryLike()))
	assert.False(t, match.Equals(exec.BinaryLike()))
}

func TestFixedSizeBinaryMatcher(t *testing.T) {
	match := exec.FixedSizeBinaryLike()

	assert.Equal(t, "fixed-size-binary-like", match.String())
	assert.False(t, match.Matches(arrow.BinaryTypes.String))
	assert.True(t, match.Matches(&arrow.Decimal128Type{Precision: 12, Scale: 5}))
	assert.True(t, match.Matches(&arrow.Decimal256Type{Precision: 12, Scale: 10}))
	assert.True(t, match.Matches(&arrow.FixedSizeBinaryType{}))
	assert.False(t, match.Equals(exec.LargeBinaryLike()))
	assert.True(t, match.Equals(exec.FixedSizeBinaryLike()))
}

func TestPrimitiveMatcher(t *testing.T) {
	match := exec.Primitive()

	assert.Equal(t, "primitive", match.String())
	assert.True(t, match.Equals(exec.Primitive()))

	types := []arrow.DataType{
		arrow.FixedWidthTypes.Boolean,
		arrow.PrimitiveTypes.Uint8,
		arrow.PrimitiveTypes.Int8,
		arrow.PrimitiveTypes.Uint16,
		arrow.PrimitiveTypes.Int16,
		arrow.PrimitiveTypes.Uint32,
		arrow.PrimitiveTypes.Int32,
		arrow.PrimitiveTypes.Uint64,
		arrow.PrimitiveTypes.Int64,
		arrow.FixedWidthTypes.Float16,
		arrow.PrimitiveTypes.Float32,
		arrow.PrimitiveTypes.Float64,
		arrow.FixedWidthTypes.Date32,
		arrow.FixedWidthTypes.Date64,
		arrow.FixedWidthTypes.Time32ms,
		arrow.FixedWidthTypes.Time64ns,
		arrow.FixedWidthTypes.Timestamp_ms,
		arrow.FixedWidthTypes.Duration_ms,
		arrow.FixedWidthTypes.MonthInterval,
		arrow.FixedWidthTypes.DayTimeInterval,
		arrow.FixedWidthTypes.MonthDayNanoInterval,
	}

	for _, typ := range types {
		assert.True(t, match.Matches(typ))
	}

	assert.False(t, match.Matches(arrow.Null))
}

func TestREEMatcher(t *testing.T) {
	tests := []struct {
		runEnds        exec.TypeMatcher
		enc            exec.TypeMatcher
		matchRunEnds   arrow.DataType
		nomatchRunEnds arrow.DataType
		matchEnc       arrow.DataType
		nomatchEnc     arrow.DataType
	}{
		{exec.Integer(), exec.Integer(), arrow.PrimitiveTypes.Int16, arrow.FixedWidthTypes.Float16, arrow.PrimitiveTypes.Int8, arrow.BinaryTypes.String},
		{exec.SameTypeID(arrow.INT32), exec.BinaryLike(), arrow.PrimitiveTypes.Int32, arrow.PrimitiveTypes.Int64, arrow.BinaryTypes.String, arrow.PrimitiveTypes.Int32},
		{exec.SameTypeID(arrow.INT64), exec.SameTypeID(arrow.STRUCT), arrow.PrimitiveTypes.Int64, arrow.PrimitiveTypes.Int32, arrow.StructOf(arrow.Field{Name: "a", Type: arrow.PrimitiveTypes.Int16}), arrow.PrimitiveTypes.Int8},
	}

	for _, tt := range tests {
		t.Run(tt.enc.String(), func(t *testing.T) {
			matcher := exec.RunEndEncoded(tt.runEnds, tt.enc)
			assert.False(t, matcher.Matches(tt.matchEnc))
			assert.True(t, matcher.Matches(arrow.RunEndEncodedOf(tt.matchRunEnds, tt.matchEnc)))
			assert.False(t, matcher.Matches(arrow.RunEndEncodedOf(tt.matchRunEnds, tt.nomatchEnc)))
			assert.False(t, matcher.Matches(arrow.RunEndEncodedOf(tt.nomatchRunEnds, tt.matchEnc)))
			assert.False(t, matcher.Matches(arrow.RunEndEncodedOf(tt.nomatchRunEnds, tt.nomatchEnc)))

			assert.Equal(t, "run_end_encoded(run_ends="+tt.runEnds.String()+", values="+tt.enc.String()+")", matcher.String())

			assert.True(t, matcher.Equals(exec.RunEndEncoded(tt.runEnds, tt.enc)))
			assert.False(t, matcher.Equals(exec.Primitive()))
			assert.False(t, matcher.Equals(exec.RunEndEncoded(exec.SameTypeID(tt.nomatchRunEnds.ID()), exec.SameTypeID(tt.nomatchEnc.ID()))))
			assert.False(t, matcher.Equals(exec.RunEndEncoded(exec.SameTypeID(tt.matchRunEnds.ID()), exec.SameTypeID(tt.nomatchEnc.ID()))))
			assert.False(t, matcher.Equals(exec.RunEndEncoded(exec.SameTypeID(tt.nomatchRunEnds.ID()), exec.SameTypeID(tt.matchEnc.ID()))))
		})
	}
}

func TestInputTypeAnyType(t *testing.T) {
	var ty exec.InputType
	assert.Equal(t, exec.InputAny, ty.Kind)
}

func TestInputType(t *testing.T) {
	ty1 := exec.NewExactInput(arrow.PrimitiveTypes.Int8)
	assert.Equal(t, exec.InputExact, ty1.Kind)
	assert.True(t, arrow.TypeEqual(arrow.PrimitiveTypes.Int8, ty1.Type))
	assert.Equal(t, "int8", ty1.String())

	ty2 := exec.NewIDInput(arrow.DECIMAL)
	assert.Equal(t, exec.InputUseMatcher, ty2.Kind)
	assert.Equal(t, "Type::DECIMAL128", ty2.String())
	assert.True(t, ty2.Matcher.Matches(&arrow.Decimal128Type{Precision: 12, Scale: 2}))
	assert.False(t, ty2.Matcher.Matches(arrow.PrimitiveTypes.Int16))

	ty3 := exec.NewMatchedInput(exec.TimestampTypeUnit(arrow.Microsecond))
	assert.Equal(t, "timestamp(us)", ty3.String())

	var ty4 exec.InputType
	assert.Equal(t, "any", ty4.String())
	// InputAny matches anything
	assert.True(t, ty4.Matches((arrow.DataType)(nil)))
}

func TestInputTypeEquals(t *testing.T) {
	t1 := exec.NewExactInput(arrow.PrimitiveTypes.Int8)
	t2 := exec.NewExactInput(arrow.PrimitiveTypes.Int8)
	t3 := exec.NewExactInput(arrow.PrimitiveTypes.Int32)

	t5 := exec.NewIDInput(arrow.DECIMAL)
	t6 := exec.NewIDInput(arrow.DECIMAL)

	assert.True(t, t1.Equals(&t2))
	assert.False(t, t1.Equals(&t3))
	assert.False(t, t1.Equals(&t5))
	assert.True(t, t5.Equals(&t5))
	assert.True(t, t5.Equals(&t6))

	var ty exec.InputType
	assert.True(t, ty.Equals(&exec.InputType{Kind: exec.InputAny}))

	// for now, an ID matcher for arrow.INT32 and a ExactInput for
	// arrow.PrimitiveTypes.Int32 are treated as being different.
	// this could be made equivalent later if desireable

	// check that field metadata is excluded from equality checks
	t7 := exec.NewExactInput(arrow.ListOfField(
		arrow.Field{Name: "item", Type: arrow.BinaryTypes.String,
			Nullable: true, Metadata: arrow.NewMetadata([]string{"foo"}, []string{"bar"})}))
	t8 := exec.NewExactInput(arrow.ListOf(arrow.BinaryTypes.String))
	assert.True(t, t7.Equals(&t8))
}

func TestInputTypeHash(t *testing.T) {
	var (
		t0 exec.InputType
		t1 = exec.NewExactInput(arrow.PrimitiveTypes.Int8)
		t2 = exec.NewIDInput(arrow.DECIMAL)
	)

	// these checks try to determine first of all whether hash
	// always returns the same value, and whether the elements
	// of the type are all incorporated into the hash
	assert.Equal(t, t0.Hash(), t0.Hash())
	assert.Equal(t, t1.Hash(), t1.Hash())
	assert.Equal(t, t2.Hash(), t2.Hash())
	assert.NotEqual(t, t0.Hash(), t1.Hash())
	assert.NotEqual(t, t0.Hash(), t2.Hash())
	assert.NotEqual(t, t1.Hash(), t2.Hash())
}

func TestInputTypeMatches(t *testing.T) {
	in1 := exec.NewExactInput(arrow.PrimitiveTypes.Int8)

	assert.True(t, in1.Matches(arrow.PrimitiveTypes.Int8))
	assert.False(t, in1.Matches(arrow.PrimitiveTypes.Int16))

	in2 := exec.NewIDInput(arrow.DECIMAL)
	assert.True(t, in2.Matches(&arrow.Decimal128Type{Precision: 12, Scale: 2}))

	ty2 := &arrow.Decimal128Type{Precision: 12, Scale: 2}
	ty3 := arrow.PrimitiveTypes.Float64

	mem := memory.NewCheckedAllocator(memory.DefaultAllocator)
	defer mem.AssertSize(t, 0)

	arr2 := array.MakeArrayOfNull(mem, ty2, 1)
	arr3 := array.MakeArrayOfNull(mem, ty3, 1)
	defer arr2.Release()
	defer arr3.Release()

	scalar2, err := scalar.GetScalar(arr2, 0)
	assert.NoError(t, err)

	datumArr := compute.NewDatum(arr2)
	defer datumArr.Release()
	datumScalar := compute.NewDatum(scalar2)
	defer datumScalar.Release()

	assert.False(t, in2.Matches(ty3))
	assert.False(t, in2.Matches(arr3.DataType()))
}

func TestOutputType(t *testing.T) {
	ty1 := exec.NewOutputType(arrow.PrimitiveTypes.Int8)
	assert.Equal(t, exec.ResolveFixed, ty1.Kind)
	assert.True(t, arrow.TypeEqual(arrow.PrimitiveTypes.Int8, ty1.Type))

	dummyResolver := func(_ *exec.KernelCtx, args []arrow.DataType) (arrow.DataType, error) {
		return arrow.PrimitiveTypes.Int32, nil
	}

	ty2 := exec.NewComputedOutputType(dummyResolver)
	assert.Equal(t, exec.ResolveComputed, ty2.Kind)

	outType2, err := ty2.Resolve(nil, nil)
	assert.NoError(t, err)
	assert.Same(t, arrow.PrimitiveTypes.Int32, outType2)

	ty3 := ty1
	assert.Equal(t, exec.ResolveFixed, ty3.Kind)
	assert.True(t, arrow.TypeEqual(ty1.Type, ty3.Type))

	ty4 := ty2
	assert.Equal(t, exec.ResolveComputed, ty4.Kind)
	outType4, err := ty4.Resolve(nil, nil)
	assert.NoError(t, err)
	assert.Same(t, arrow.PrimitiveTypes.Int32, outType4)

	assert.Equal(t, "int8", ty3.String())
	assert.Equal(t, "computed", ty4.String())
}

func TestOutputTypeResolve(t *testing.T) {
	ty1 := exec.NewOutputType(arrow.PrimitiveTypes.Int32)

	result, err := ty1.Resolve(nil, nil)
	assert.NoError(t, err)
	assert.Same(t, arrow.PrimitiveTypes.Int32, result)

	result, err = ty1.Resolve(nil, []arrow.DataType{arrow.PrimitiveTypes.Int8})
	assert.NoError(t, err)
	assert.Same(t, arrow.PrimitiveTypes.Int32, result)

	result, err = ty1.Resolve(nil, []arrow.DataType{arrow.PrimitiveTypes.Int8, arrow.PrimitiveTypes.Int8})
	assert.NoError(t, err)
	assert.Same(t, arrow.PrimitiveTypes.Int32, result)

	resolver := func(_ *exec.KernelCtx, args []arrow.DataType) (arrow.DataType, error) {
		return args[0], nil
	}
	ty2 := exec.NewComputedOutputType(resolver)

	result, err = ty2.Resolve(nil, []arrow.DataType{arrow.BinaryTypes.String})
	assert.NoError(t, err)
	assert.Same(t, arrow.BinaryTypes.String, result)

	// type resolver that returns an error
	ty3 := exec.NewComputedOutputType(func(_ *exec.KernelCtx, dt []arrow.DataType) (arrow.DataType, error) {
		// checking the value types versus the function arity should be validated
		// elsewhere. this is just for illustration purposes
		if len(dt) == 0 {
			return nil, fmt.Errorf("%w: need at least one argument", arrow.ErrInvalid)
		}
		return dt[0], nil
	})

	_, err = ty3.Resolve(nil, []arrow.DataType{})
	assert.ErrorIs(t, err, arrow.ErrInvalid)

	// resolver returns a fixed value
	ty4 := exec.NewComputedOutputType(func(*exec.KernelCtx, []arrow.DataType) (arrow.DataType, error) {
		return arrow.PrimitiveTypes.Int32, nil
	})
	result, err = ty4.Resolve(nil, []arrow.DataType{arrow.PrimitiveTypes.Int8})
	assert.NoError(t, err)
	assert.Same(t, arrow.PrimitiveTypes.Int32, result)
	result, err = ty4.Resolve(nil, []arrow.DataType{})
	assert.NoError(t, err)
	assert.Same(t, arrow.PrimitiveTypes.Int32, result)
}

func TestKernelSignatureEquals(t *testing.T) {
	sig1 := exec.KernelSignature{
		InputTypes: []exec.InputType{},
		OutType:    exec.NewOutputType(arrow.BinaryTypes.String)}
	sig1Copy := exec.KernelSignature{
		InputTypes: []exec.InputType{},
		OutType:    exec.NewOutputType(arrow.BinaryTypes.String)}
	sig2 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8)},
		OutType: exec.NewOutputType(arrow.BinaryTypes.String),
	}

	// output type doesn't matter (for now)
	sig3 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8)},
		OutType: exec.NewOutputType(arrow.PrimitiveTypes.Int32),
	}

	sig4 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8),
			exec.NewExactInput(arrow.PrimitiveTypes.Int16),
		},
		OutType: exec.NewOutputType(arrow.BinaryTypes.String),
	}
	sig4Copy := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8),
			exec.NewExactInput(arrow.PrimitiveTypes.Int16),
		},
		OutType: exec.NewOutputType(arrow.BinaryTypes.String),
	}
	sig5 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8),
			exec.NewExactInput(arrow.PrimitiveTypes.Int16),
			exec.NewExactInput(arrow.PrimitiveTypes.Int32),
		},
		OutType: exec.NewOutputType(arrow.BinaryTypes.String),
	}

	assert.True(t, sig1.Equals(sig1))
	assert.True(t, sig2.Equals(sig3))
	assert.False(t, sig3.Equals(sig4))

	// different sig objects but same sig
	assert.True(t, sig1.Equals(sig1Copy))
	assert.True(t, sig4.Equals(sig4Copy))

	// match first 2 args, but not third
	assert.False(t, sig4.Equals(sig5))
}

func TestKernelSignatureVarArgsEqual(t *testing.T) {
	sig1 := exec.KernelSignature{
		InputTypes: []exec.InputType{exec.NewExactInput(arrow.PrimitiveTypes.Int8)},
		OutType:    exec.NewOutputType(arrow.BinaryTypes.String),
		IsVarArgs:  true,
	}
	sig2 := exec.KernelSignature{
		InputTypes: []exec.InputType{exec.NewExactInput(arrow.PrimitiveTypes.Int8)},
		OutType:    exec.NewOutputType(arrow.BinaryTypes.String),
		IsVarArgs:  true,
	}
	sig3 := exec.KernelSignature{
		InputTypes: []exec.InputType{exec.NewExactInput(arrow.PrimitiveTypes.Int8)},
		OutType:    exec.NewOutputType(arrow.BinaryTypes.String),
	}

	assert.True(t, sig1.Equals(sig2))
	assert.False(t, sig2.Equals(sig3))
}

func TestKernelSignatureHash(t *testing.T) {
	sig1 := exec.KernelSignature{
		InputTypes: []exec.InputType{},
		OutType:    exec.NewOutputType(arrow.BinaryTypes.String),
	}
	sig2 := exec.KernelSignature{
		InputTypes: []exec.InputType{exec.NewExactInput(arrow.PrimitiveTypes.Int8)},
		OutType:    exec.NewOutputType(arrow.BinaryTypes.String),
	}
	sig3 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8),
			exec.NewExactInput(arrow.PrimitiveTypes.Int32)},
		OutType: exec.NewOutputType(arrow.BinaryTypes.String),
	}

	assert.Equal(t, sig1.Hash(), sig1.Hash())
	assert.Equal(t, sig2.Hash(), sig2.Hash())
	assert.NotEqual(t, sig1.Hash(), sig2.Hash())
	assert.NotEqual(t, sig2.Hash(), sig3.Hash())
}

func TestKernelSignatureMatchesInputs(t *testing.T) {
	// () -> boolean
	sig1 := exec.KernelSignature{
		OutType: exec.NewOutputType(arrow.FixedWidthTypes.Boolean)}

	assert.True(t, sig1.MatchesInputs([]arrow.DataType{}))
	assert.False(t, sig1.MatchesInputs([]arrow.DataType{arrow.PrimitiveTypes.Int8}))

	// (int8, decimal) -> boolean
	sig2 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8),
			exec.NewIDInput(arrow.DECIMAL)},
		OutType: exec.NewOutputType(arrow.FixedWidthTypes.Boolean),
	}
	assert.False(t, sig2.MatchesInputs([]arrow.DataType{}))
	assert.False(t, sig2.MatchesInputs([]arrow.DataType{arrow.PrimitiveTypes.Int8}))
	assert.True(t, sig2.MatchesInputs([]arrow.DataType{
		arrow.PrimitiveTypes.Int8,
		&arrow.Decimal128Type{Precision: 12, Scale: 2}}))

	// (int8, int32) -> boolean
	sig3 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8),
			exec.NewExactInput(arrow.PrimitiveTypes.Int32),
		},
		OutType: exec.NewOutputType(arrow.FixedWidthTypes.Boolean),
	}
	assert.False(t, sig3.MatchesInputs(nil))
	assert.True(t, sig3.MatchesInputs([]arrow.DataType{arrow.PrimitiveTypes.Int8, arrow.PrimitiveTypes.Int32}))
	assert.False(t, sig3.MatchesInputs([]arrow.DataType{arrow.PrimitiveTypes.Int8, arrow.PrimitiveTypes.Int16}))
}

func TestKernelSignatureVarArgsMatchesInputs(t *testing.T) {
	{
		sig := exec.KernelSignature{
			InputTypes: []exec.InputType{exec.NewExactInput(arrow.PrimitiveTypes.Int8)},
			OutType:    exec.NewOutputType(arrow.BinaryTypes.String),
			IsVarArgs:  true,
		}

		args := []arrow.DataType{arrow.PrimitiveTypes.Int8}
		assert.True(t, sig.MatchesInputs(args))
		args = append(args, arrow.PrimitiveTypes.Int8, arrow.PrimitiveTypes.Int8)
		assert.True(t, sig.MatchesInputs(args))
		args = append(args, arrow.PrimitiveTypes.Int32)
		assert.False(t, sig.MatchesInputs(args))
	}
	{
		sig := exec.KernelSignature{
			InputTypes: []exec.InputType{
				exec.NewExactInput(arrow.PrimitiveTypes.Int8),
				exec.NewExactInput(arrow.BinaryTypes.String),
			},
			OutType:   exec.NewOutputType(arrow.BinaryTypes.String),
			IsVarArgs: true,
		}

		args := []arrow.DataType{arrow.PrimitiveTypes.Int8}
		assert.True(t, sig.MatchesInputs(args))
		args = append(args, arrow.BinaryTypes.String, arrow.BinaryTypes.String)
		assert.True(t, sig.MatchesInputs(args))
		args = append(args, arrow.PrimitiveTypes.Int32)
		assert.False(t, sig.MatchesInputs(args))
	}
}

func TestKernelSignatureToString(t *testing.T) {
	inTypes := []exec.InputType{
		exec.NewExactInput(arrow.PrimitiveTypes.Int8),
		exec.NewIDInput(arrow.DECIMAL),
		exec.NewExactInput(arrow.BinaryTypes.String),
	}

	sig := exec.KernelSignature{
		InputTypes: inTypes, OutType: exec.NewOutputType(arrow.BinaryTypes.String),
	}
	assert.Equal(t, "(int8, Type::DECIMAL128, utf8) -> utf8", sig.String())

	outType := exec.NewComputedOutputType(func(*exec.KernelCtx, []arrow.DataType) (arrow.DataType, error) {
		return nil, arrow.ErrInvalid
	})
	sig2 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8),
			exec.NewIDInput(arrow.DECIMAL)},
		OutType: outType,
	}
	assert.Equal(t, "(int8, Type::DECIMAL128) -> computed", sig2.String())
}

func TestKernelSignatureVarArgsToString(t *testing.T) {
	sig1 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.PrimitiveTypes.Int8)},
		OutType:   exec.NewOutputType(arrow.BinaryTypes.String),
		IsVarArgs: true,
	}
	assert.Equal(t, "varargs[int8*] -> utf8", sig1.String())

	sig2 := exec.KernelSignature{
		InputTypes: []exec.InputType{
			exec.NewExactInput(arrow.BinaryTypes.String),
			exec.NewExactInput(arrow.PrimitiveTypes.Int8)},
		OutType:   exec.NewOutputType(arrow.BinaryTypes.String),
		IsVarArgs: true,
	}
	assert.Equal(t, "varargs[utf8, int8*] -> utf8", sig2.String())
}