82 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			Go
		
	
	
	
			
		
		
	
	
			82 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			Go
		
	
	
	
| // Copyright 2015 The Prometheus Authors
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| // Licensed under the Apache License, Version 2.0 (the "License");
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| // you may not use this file except in compliance with the License.
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| // You may obtain a copy of the License at
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| //
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| // http://www.apache.org/licenses/LICENSE-2.0
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| //
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| // Unless required by applicable law or agreed to in writing, software
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| // distributed under the License is distributed on an "AS IS" BASIS,
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| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| // See the License for the specific language governing permissions and
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| // limitations under the License.
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| 
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| package promql
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| 
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| import (
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| 	"fmt"
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| 	"math"
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| 	"testing"
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| 
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| 	"github.com/stretchr/testify/require"
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| )
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| 
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| func TestKahanSumInc(t *testing.T) {
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| 	testCases := map[string]struct {
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| 		first    float64
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| 		second   float64
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| 		expected float64
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| 	}{
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| 		"+Inf + anything = +Inf": {
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| 			first:    math.Inf(1),
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| 			second:   2.0,
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| 			expected: math.Inf(1),
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| 		},
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| 		"-Inf + anything = -Inf": {
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| 			first:    math.Inf(-1),
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| 			second:   2.0,
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| 			expected: math.Inf(-1),
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| 		},
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| 		"+Inf + -Inf = NaN": {
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| 			first:    math.Inf(1),
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| 			second:   math.Inf(-1),
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| 			expected: math.NaN(),
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| 		},
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| 		"NaN + anything = NaN": {
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| 			first:    math.NaN(),
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| 			second:   2,
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| 			expected: math.NaN(),
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| 		},
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| 		"NaN + Inf = NaN": {
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| 			first:    math.NaN(),
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| 			second:   math.Inf(1),
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| 			expected: math.NaN(),
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| 		},
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| 		"NaN + -Inf = NaN": {
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| 			first:    math.NaN(),
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| 			second:   math.Inf(-1),
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| 			expected: math.NaN(),
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| 		},
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| 	}
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| 
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| 	runTest := func(t *testing.T, a, b, expected float64) {
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| 		t.Run(fmt.Sprintf("%v + %v = %v", a, b, expected), func(t *testing.T) {
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| 			sum, c := kahanSumInc(b, a, 0)
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| 			result := sum + c
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| 
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| 			if math.IsNaN(expected) {
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| 				require.Truef(t, math.IsNaN(result), "expected result to be NaN, but got %v (from %v + %v)", result, sum, c)
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| 			} else {
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| 				require.Equalf(t, expected, result, "expected result to be %v, but got %v (from %v + %v)", expected, result, sum, c)
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| 			}
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| 		})
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| 	}
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| 
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| 	for name, testCase := range testCases {
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| 		t.Run(name, func(t *testing.T) {
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| 			runTest(t, testCase.first, testCase.second, testCase.expected)
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| 			runTest(t, testCase.second, testCase.first, testCase.expected)
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| 		})
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| 	}
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| }
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