| // Copyright 2023 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package main |
| |
| import ( |
| "fmt" |
| "math" |
| ) |
| |
| func main() { |
| TestMinFloat() |
| TestMaxFloat() |
| TestMinMaxInt() |
| TestMinMaxUint8() |
| TestMinMaxString() |
| } |
| |
| func errorf(format string, args ...any) { panic(fmt.Sprintf(format, args...)) } |
| func fatalf(format string, args ...any) { panic(fmt.Sprintf(format, args...)) } |
| |
| // derived from $GOROOT/src/runtime/minmax_test.go |
| |
| var ( |
| zero = math.Copysign(0, +1) |
| negZero = math.Copysign(0, -1) |
| inf = math.Inf(+1) |
| negInf = math.Inf(-1) |
| nan = math.NaN() |
| ) |
| |
| var tests = []struct{ min, max float64 }{ |
| {1, 2}, |
| {-2, 1}, |
| {negZero, zero}, |
| {zero, inf}, |
| {negInf, zero}, |
| {negInf, inf}, |
| {1, inf}, |
| {negInf, 1}, |
| } |
| |
| var all = []float64{1, 2, -1, -2, zero, negZero, inf, negInf, nan} |
| |
| func eq(x, y float64) bool { |
| return x == y && math.Signbit(x) == math.Signbit(y) |
| } |
| |
| func TestMinFloat() { |
| for _, tt := range tests { |
| if z := min(tt.min, tt.max); !eq(z, tt.min) { |
| errorf("min(%v, %v) = %v, want %v", tt.min, tt.max, z, tt.min) |
| } |
| if z := min(tt.max, tt.min); !eq(z, tt.min) { |
| errorf("min(%v, %v) = %v, want %v", tt.max, tt.min, z, tt.min) |
| } |
| } |
| for _, x := range all { |
| if z := min(nan, x); !math.IsNaN(z) { |
| errorf("min(%v, %v) = %v, want %v", nan, x, z, nan) |
| } |
| if z := min(x, nan); !math.IsNaN(z) { |
| errorf("min(%v, %v) = %v, want %v", nan, x, z, nan) |
| } |
| } |
| } |
| |
| func TestMaxFloat() { |
| for _, tt := range tests { |
| if z := max(tt.min, tt.max); !eq(z, tt.max) { |
| errorf("max(%v, %v) = %v, want %v", tt.min, tt.max, z, tt.max) |
| } |
| if z := max(tt.max, tt.min); !eq(z, tt.max) { |
| errorf("max(%v, %v) = %v, want %v", tt.max, tt.min, z, tt.max) |
| } |
| } |
| for _, x := range all { |
| if z := max(nan, x); !math.IsNaN(z) { |
| errorf("min(%v, %v) = %v, want %v", nan, x, z, nan) |
| } |
| if z := max(x, nan); !math.IsNaN(z) { |
| errorf("min(%v, %v) = %v, want %v", nan, x, z, nan) |
| } |
| } |
| } |
| |
| // testMinMax tests that min/max behave correctly on every pair of |
| // values in vals. |
| // |
| // vals should be a sequence of values in strictly ascending order. |
| func testMinMax[T int | uint8 | string](vals ...T) { |
| for i, x := range vals { |
| for _, y := range vals[i+1:] { |
| if !(x < y) { |
| fatalf("values out of order: !(%v < %v)", x, y) |
| } |
| |
| if z := min(x, y); z != x { |
| errorf("min(%v, %v) = %v, want %v", x, y, z, x) |
| } |
| if z := min(y, x); z != x { |
| errorf("min(%v, %v) = %v, want %v", y, x, z, x) |
| } |
| |
| if z := max(x, y); z != y { |
| errorf("max(%v, %v) = %v, want %v", x, y, z, y) |
| } |
| if z := max(y, x); z != y { |
| errorf("max(%v, %v) = %v, want %v", y, x, z, y) |
| } |
| } |
| } |
| } |
| |
| func TestMinMaxInt() { testMinMax[int](-7, 0, 9) } |
| func TestMinMaxUint8() { testMinMax[uint8](0, 1, 2, 4, 7) } |
| func TestMinMaxString() { testMinMax[string]("a", "b", "c") } |