color_test.go

Documentation: image/color

		 1  // Copyright 2017 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 color
		 6  
		 7  import (
		 8  	"testing"
		 9  	"testing/quick"
		10  )
		11  
		12  func TestSqDiff(t *testing.T) {
		13  	// canonical sqDiff implementation
		14  	orig := func(x, y uint32) uint32 {
		15  		var d uint32
		16  		if x > y {
		17  			d = uint32(x - y)
		18  		} else {
		19  			d = uint32(y - x)
		20  		}
		21  		return (d * d) >> 2
		22  	}
		23  	testCases := []uint32{
		24  		0,
		25  		1,
		26  		2,
		27  		0x0fffd,
		28  		0x0fffe,
		29  		0x0ffff,
		30  		0x10000,
		31  		0x10001,
		32  		0x10002,
		33  		0xfffffffd,
		34  		0xfffffffe,
		35  		0xffffffff,
		36  	}
		37  	for _, x := range testCases {
		38  		for _, y := range testCases {
		39  			if got, want := sqDiff(x, y), orig(x, y); got != want {
		40  				t.Fatalf("sqDiff(%#x, %#x): got %d, want %d", x, y, got, want)
		41  			}
		42  		}
		43  	}
		44  	if err := quick.CheckEqual(orig, sqDiff, &quick.Config{MaxCountScale: 10}); err != nil {
		45  		t.Fatal(err)
		46  	}
		47  }
		48
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