strconv: use Run for some benchmarks

This serves as an example of table-driven benchmarks which are analoguous to the common pattern for table-driven tests.

Change-Id: I47f94c121a7117dd1e4ba03b3f2f8bcb5da38063
Reviewed-on: https://go-review.googlesource.com/23470
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

src/strconv/ftoa_test.go

@@ -183,59 +183,50 @@ func TestFtoaRandom(t *testing.T) {
 	}
 }
 
-func BenchmarkFormatFloatDecimal(b *testing.B) {
-	for i := 0; i < b.N; i++ {
-		FormatFloat(33909, 'g', -1, 64)
-	}
+var ftoaBenches = []struct {
+	name    string
+	float   float64
+	fmt     byte
+	prec    int
+	bitSize int
+}{
+	{"Decimal", 33909, 'g', -1, 64},
+	{"Float", 339.7784, 'g', -1, 64},
+	{"Exp", -5.09e75, 'g', -1, 64},
+	{"NegExp", -5.11e-95, 'g', -1, 64},
+
+	{"Big", 123456789123456789123456789, 'g', -1, 64},
+	{"BinaryExp", -1, 'b', -1, 64},
+
+	{"32Integer", 33909, 'g', -1, 32},
+	{"32ExactFraction", 3.375, 'g', -1, 32},
+	{"32Point", 339.7784, 'g', -1, 32},
+	{"32Exp", -5.09e25, 'g', -1, 32},
+	{"32NegExp", -5.11e-25, 'g', -1, 32},
+
+	{"64Fixed1", 123456, 'e', 3, 64},
+	{"64Fixed2", 123.456, 'e', 3, 64},
+	{"64Fixed3", 1.23456e+78, 'e', 3, 64},
+	{"64Fixed4", 1.23456e-78, 'e', 3, 64},
 }
 
 func BenchmarkFormatFloat(b *testing.B) {
-	for i := 0; i < b.N; i++ {
-		FormatFloat(339.7784, 'g', -1, 64)
-	}
-}
-
-func BenchmarkFormatFloatExp(b *testing.B) {
-	for i := 0; i < b.N; i++ {
-		FormatFloat(-5.09e75, 'g', -1, 64)
-	}
-}
-
-func BenchmarkFormatFloatNegExp(b *testing.B) {
-	for i := 0; i < b.N; i++ {
-		FormatFloat(-5.11e-95, 'g', -1, 64)
-	}
-}
-
-func BenchmarkFormatFloatBig(b *testing.B) {
-	for i := 0; i < b.N; i++ {
-		FormatFloat(123456789123456789123456789, 'g', -1, 64)
+	for _, c := range ftoaBenches {
+		b.Run(c.name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				FormatFloat(c.float, c.fmt, c.prec, c.bitSize)
+			}
+		})
 	}
 }
 
-func benchmarkAppendFloat(b *testing.B, f float64, fmt byte, prec, bitSize int) {
+func BenchmarkAppendFloat(b *testing.B) {
 	dst := make([]byte, 30)
-	for i := 0; i < b.N; i++ {
-		AppendFloat(dst[:0], f, fmt, prec, bitSize)
+	for _, c := range ftoaBenches {
+		b.Run(c.name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				AppendFloat(dst[:0], c.float, c.fmt, c.prec, c.bitSize)
+			}
+		})
 	}
 }
-
-func BenchmarkAppendFloatDecimal(b *testing.B) { benchmarkAppendFloat(b, 33909, 'g', -1, 64) }
-func BenchmarkAppendFloat(b *testing.B)        { benchmarkAppendFloat(b, 339.7784, 'g', -1, 64) }
-func BenchmarkAppendFloatExp(b *testing.B)     { benchmarkAppendFloat(b, -5.09e75, 'g', -1, 64) }
-func BenchmarkAppendFloatNegExp(b *testing.B)  { benchmarkAppendFloat(b, -5.11e-95, 'g', -1, 64) }
-func BenchmarkAppendFloatBig(b *testing.B) {
-	benchmarkAppendFloat(b, 123456789123456789123456789, 'g', -1, 64)
-}
-func BenchmarkAppendFloatBinaryExp(b *testing.B) { benchmarkAppendFloat(b, -1, 'b', -1, 64) }
-
-func BenchmarkAppendFloat32Integer(b *testing.B)       { benchmarkAppendFloat(b, 33909, 'g', -1, 32) }
-func BenchmarkAppendFloat32ExactFraction(b *testing.B) { benchmarkAppendFloat(b, 3.375, 'g', -1, 32) }
-func BenchmarkAppendFloat32Point(b *testing.B)         { benchmarkAppendFloat(b, 339.7784, 'g', -1, 32) }
-func BenchmarkAppendFloat32Exp(b *testing.B)           { benchmarkAppendFloat(b, -5.09e25, 'g', -1, 32) }
-func BenchmarkAppendFloat32NegExp(b *testing.B)        { benchmarkAppendFloat(b, -5.11e-25, 'g', -1, 32) }
-
-func BenchmarkAppendFloat64Fixed1(b *testing.B) { benchmarkAppendFloat(b, 123456, 'e', 3, 64) }
-func BenchmarkAppendFloat64Fixed2(b *testing.B) { benchmarkAppendFloat(b, 123.456, 'e', 3, 64) }
-func BenchmarkAppendFloat64Fixed3(b *testing.B) { benchmarkAppendFloat(b, 1.23456e+78, 'e', 3, 64) }
-func BenchmarkAppendFloat64Fixed4(b *testing.B) { benchmarkAppendFloat(b, 1.23456e-78, 'e', 3, 64) }