math/big: move exhaustive tests behind -long flag

This way you can still run 'go test' or 'go bench -run Foo'
without wondering why it is taking so very long.

Change-Id: Icfa097a6deb1d6682acb7be9f34729215c29eabb
Reviewed-on: https://go-review.googlesource.com/30707Reviewed-by: Robert Griesemer <gri@golang.org>

src/math/big/float_test.go

@@ -5,6 +5,7 @@
 package big
 
 import (
+	"flag"
 	"fmt"
 	"math"
 	"strconv"
@@ -1495,12 +1496,14 @@ func TestFloatQuo(t *testing.T) {
 	}
 }
 
+var long = flag.Bool("long", false, "run very long tests")
+
 // TestFloatQuoSmoke tests all divisions x/y for values x, y in the range [-n, +n];
 // it serves as a smoke test for basic correctness of division.
 func TestFloatQuoSmoke(t *testing.T) {
-	n := 1000
-	if testing.Short() {
-		n = 10
+	n := 10
+	if *long {
+		n = 1000
 	}
 
 	const dprec = 3         // max. precision variation

src/math/big/rat_test.go

@@ -382,9 +382,9 @@ func TestFloat32Distribution(t *testing.T) {
 		9,
 		11,
 	}
-	var winc, einc = uint64(1), 1 // soak test (~1.5s on x86-64)
+	var winc, einc = uint64(5), 15 // quick test (~60ms on x86-64)
 	if testing.Short() {
-		winc, einc = 5, 15 // quick test (~60ms on x86-64)
+		winc, einc = uint64(1), 1 // soak test (~1.5s on x86-64)
 	}
 
 	for _, sign := range "+-" {
@@ -430,9 +430,9 @@ func TestFloat64Distribution(t *testing.T) {
 		9,
 		11,
 	}
-	var winc, einc = uint64(1), 1 // soak test (~75s on x86-64)
-	if testing.Short() {
-		winc, einc = 10, 500 // quick test (~12ms on x86-64)
+	var winc, einc = uint64(10), 500 // quick test (~12ms on x86-64)
+	if *long {
+		winc, einc = uint64(1), 1 // soak test (~75s on x86-64)
 	}
 
 	for _, sign := range "+-" {

src/math/big/ratconv_test.go

@@ -144,7 +144,7 @@ func TestFloatString(t *testing.T) {
 }
 
 // Test inputs to Rat.SetString. The prefix "long:" causes the test
-// to be skipped in --test.short mode.  (The threshold is about 500us.)
+// to be skipped except in -long mode.  (The threshold is about 500us.)
 var float64inputs = []string{
 	// Constants plundered from strconv/testfp.txt.
 
@@ -350,7 +350,7 @@ func isFinite(f float64) bool {
 func TestFloat32SpecialCases(t *testing.T) {
 	for _, input := range float64inputs {
 		if strings.HasPrefix(input, "long:") {
-			if testing.Short() {
+			if !*long {
 				continue
 			}
 			input = input[len("long:"):]
@@ -406,7 +406,7 @@ func TestFloat32SpecialCases(t *testing.T) {
 func TestFloat64SpecialCases(t *testing.T) {
 	for _, input := range float64inputs {
 		if strings.HasPrefix(input, "long:") {
-			if testing.Short() {
+			if !*long {
 				continue
 			}
 			input = input[len("long:"):]