minmax.go

Documentation: golang.org/x/tools/go/ssa/interp/testdata

     1  // Copyright 2023 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package main
     6  
     7  import (
     8  	"fmt"
     9  	"math"
    10  )
    11  
    12  func main() {
    13  	TestMinFloat()
    14  	TestMaxFloat()
    15  	TestMinMaxInt()
    16  	TestMinMaxUint8()
    17  	TestMinMaxString()
    18  }
    19  
    20  func errorf(format string, args ...any) { panic(fmt.Sprintf(format, args...)) }
    21  func fatalf(format string, args ...any) { panic(fmt.Sprintf(format, args...)) }
    22  
    23  // derived from $GOROOT/src/runtime/minmax_test.go
    24  
    25  var (
    26  	zero    = math.Copysign(0, +1)
    27  	negZero = math.Copysign(0, -1)
    28  	inf     = math.Inf(+1)
    29  	negInf  = math.Inf(-1)
    30  	nan     = math.NaN()
    31  )
    32  
    33  var tests = []struct{ min, max float64 }{
    34  	{1, 2},
    35  	{-2, 1},
    36  	{negZero, zero},
    37  	{zero, inf},
    38  	{negInf, zero},
    39  	{negInf, inf},
    40  	{1, inf},
    41  	{negInf, 1},
    42  }
    43  
    44  var all = []float64{1, 2, -1, -2, zero, negZero, inf, negInf, nan}
    45  
    46  func eq(x, y float64) bool {
    47  	return x == y && math.Signbit(x) == math.Signbit(y)
    48  }
    49  
    50  func TestMinFloat() {
    51  	for _, tt := range tests {
    52  		if z := min(tt.min, tt.max); !eq(z, tt.min) {
    53  			errorf("min(%v, %v) = %v, want %v", tt.min, tt.max, z, tt.min)
    54  		}
    55  		if z := min(tt.max, tt.min); !eq(z, tt.min) {
    56  			errorf("min(%v, %v) = %v, want %v", tt.max, tt.min, z, tt.min)
    57  		}
    58  	}
    59  	for _, x := range all {
    60  		if z := min(nan, x); !math.IsNaN(z) {
    61  			errorf("min(%v, %v) = %v, want %v", nan, x, z, nan)
    62  		}
    63  		if z := min(x, nan); !math.IsNaN(z) {
    64  			errorf("min(%v, %v) = %v, want %v", nan, x, z, nan)
    65  		}
    66  	}
    67  }
    68  
    69  func TestMaxFloat() {
    70  	for _, tt := range tests {
    71  		if z := max(tt.min, tt.max); !eq(z, tt.max) {
    72  			errorf("max(%v, %v) = %v, want %v", tt.min, tt.max, z, tt.max)
    73  		}
    74  		if z := max(tt.max, tt.min); !eq(z, tt.max) {
    75  			errorf("max(%v, %v) = %v, want %v", tt.max, tt.min, z, tt.max)
    76  		}
    77  	}
    78  	for _, x := range all {
    79  		if z := max(nan, x); !math.IsNaN(z) {
    80  			errorf("min(%v, %v) = %v, want %v", nan, x, z, nan)
    81  		}
    82  		if z := max(x, nan); !math.IsNaN(z) {
    83  			errorf("min(%v, %v) = %v, want %v", nan, x, z, nan)
    84  		}
    85  	}
    86  }
    87  
    88  // testMinMax tests that min/max behave correctly on every pair of
    89  // values in vals.
    90  //
    91  // vals should be a sequence of values in strictly ascending order.
    92  func testMinMax[T int | uint8 | string](vals ...T) {
    93  	for i, x := range vals {
    94  		for _, y := range vals[i+1:] {
    95  			if !(x < y) {
    96  				fatalf("values out of order: !(%v < %v)", x, y)
    97  			}
    98  
    99  			if z := min(x, y); z != x {
   100  				errorf("min(%v, %v) = %v, want %v", x, y, z, x)
   101  			}
   102  			if z := min(y, x); z != x {
   103  				errorf("min(%v, %v) = %v, want %v", y, x, z, x)
   104  			}
   105  
   106  			if z := max(x, y); z != y {
   107  				errorf("max(%v, %v) = %v, want %v", x, y, z, y)
   108  			}
   109  			if z := max(y, x); z != y {
   110  				errorf("max(%v, %v) = %v, want %v", y, x, z, y)
   111  			}
   112  		}
   113  	}
   114  }
   115  
   116  func TestMinMaxInt()    { testMinMax[int](-7, 0, 9) }
   117  func TestMinMaxUint8()  { testMinMax[uint8](0, 1, 2, 4, 7) }
   118  func TestMinMaxString() { testMinMax[string]("a", "b", "c") }
   119
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