diff --git a/prometheus/histogram_test.go b/prometheus/histogram_test.go index 80a318903..e745aa1ec 100644 --- a/prometheus/histogram_test.go +++ b/prometheus/histogram_test.go @@ -29,6 +29,8 @@ import ( "github.com/golang/protobuf/proto" "google.golang.org/protobuf/types/known/timestamppb" + "github.com/prometheus/client_golang/prometheus/internal" + dto "github.com/prometheus/client_model/go" ) @@ -356,13 +358,12 @@ func TestBuckets(t *testing.T) { got = ExponentialBucketsRange(1, 100, 10) want = []float64{ - 1.0, 1.6681005372000588, 2.782559402207125, - 4.641588833612779, 7.742636826811273, 12.915496650148842, - 21.544346900318846, 35.93813663804629, 59.94842503189414, - 100.00000000000007, + 1.0, 1.6681, 2.7825, 4.6415, 7.7426, 12.9154, 21.5443, + 35.9381, 59.9484, 100.0000, } - if !reflect.DeepEqual(got, want) { - t.Errorf("exponential buckets range: got %v, want %v", got, want) + const epsilon = 0.0001 + if !internal.AlmostEqualFloat64s(got, want, epsilon) { + t.Errorf("exponential buckets range: got %v, want %v (epsilon %f)", got, want, epsilon) } } diff --git a/prometheus/internal/almost_equal.go b/prometheus/internal/almost_equal.go new file mode 100644 index 000000000..1ed5abe74 --- /dev/null +++ b/prometheus/internal/almost_equal.go @@ -0,0 +1,60 @@ +// Copyright (c) 2015 Björn Rabenstein +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in all +// copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +// SOFTWARE. +// +// The code in this package is copy/paste to avoid a dependency. Hence this file +// carries the copyright of the original repo. +// https://github.com/beorn7/floats +package internal + +import ( + "math" +) + +// minNormalFloat64 is the smallest positive normal value of type float64. +var minNormalFloat64 = math.Float64frombits(0x0010000000000000) + +// AlmostEqualFloat64 returns true if a and b are equal within a relative error +// of epsilon. See http://floating-point-gui.de/errors/comparison/ for the +// details of the applied method. +func AlmostEqualFloat64(a, b, epsilon float64) bool { + if a == b { + return true + } + absA := math.Abs(a) + absB := math.Abs(b) + diff := math.Abs(a - b) + if a == 0 || b == 0 || absA+absB < minNormalFloat64 { + return diff < epsilon*minNormalFloat64 + } + return diff/math.Min(absA+absB, math.MaxFloat64) < epsilon +} + +// AlmostEqualFloat64s is the slice form of AlmostEqualFloat64. +func AlmostEqualFloat64s(a, b []float64, epsilon float64) bool { + if len(a) != len(b) { + return false + } + for i := range a { + if !AlmostEqualFloat64(a[i], b[i], epsilon) { + return false + } + } + return true +}