[dev.fuzz] testing: report T.Deadline when running seed values

T.Deadline should return the test deadline, set with -timeout. When
fuzz targets are run with seed values as unit tests, either with or
without -fuzz, T.Deadline should work inside the fuzz function.

There is no deadline when fuzzing, even if -fuzztime is set, since
workers may have much shorter deadlines, and fuzz function behavior
shouldn't be time-dependent anyway.

Fixes #46220

Change-Id: I84aaeb9d7bfdc12bdcb6f1ab3fe67b3067ad2dfe
Reviewed-on: https://go-review.googlesource.com/c/go/+/330509
Trust: Jay Conrod <jayconrod@google.com>
Trust: Katie Hockman <katie@golang.org>
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>

diff --git a/src/cmd/go/testdata/script/test_fuzz_deadline.txt b/src/cmd/go/testdata/script/test_fuzz_deadline.txt
new file mode 100644 (file)
index 0000000..f082647
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_deadline.txt
@@ -0,0 +1,37 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+[short] skip
+
+# The fuzz function should be able to detect whether -timeout
+# was set with T.Deadline. Note there is no F.Deadline, and
+# there is no timeout while fuzzing, even if -fuzztime is set.
+go test -run=FuzzDeadline -wantdeadline=true # -timeout defaults to 10m
+go test -run=FuzzDeadline -timeout=0 -wantdeadline=false
+! go test -run=FuzzDeadline -timeout=1s -wantdeadline=false
+go test -run=FuzzDeadline -timeout=1s -wantdeadline=true
+go test -fuzz=FuzzDeadline -timeout=0 -fuzztime=1s -wantdeadline=false
+go test -fuzz=FuzzDeadline -timeout=0 -fuzztime=100x -wantdeadline=false
+
+-- go.mod --
+module fzz
+
+go 1.16
+-- fuzz_deadline_test.go --
+package fuzz_test
+
+import (
+       "flag"
+       "testing"
+)
+
+var wantDeadline = flag.Bool("wantdeadline", false, "whether the test should have a deadline")
+
+func FuzzDeadline(f *testing.F) {
+       f.Add("run once")
+       f.Fuzz(func (t *testing.T, _ string) {
+               if _, hasDeadline := t.Deadline(); hasDeadline != *wantDeadline {
+                       t.Fatalf("function got %v; want %v", hasDeadline, *wantDeadline)
+               }
+       })
+}

diff --git a/src/testing/fuzz.go b/src/testing/fuzz.go
index fc1212b1424a84900441652737b117f085d9bc74..55e5397193e4ceb353987e021e51dda6f3aaed21 100644 (file)
--- a/src/testing/fuzz.go
+++ b/src/testing/fuzz.go
@@ -491,13 +491,14 @@ type fuzzContext struct {
 // runFuzzTargets runs the fuzz targets matching the pattern for -run. This will
 // only run the f.Fuzz function for each seed corpus without using the fuzzing
 // engine to generate or mutate inputs.
-func runFuzzTargets(deps testDeps, fuzzTargets []InternalFuzzTarget) (ran, ok bool) {
+func runFuzzTargets(deps testDeps, fuzzTargets []InternalFuzzTarget, deadline time.Time) (ran, ok bool) {
        ok = true
        if len(fuzzTargets) == 0 || *isFuzzWorker {
                return ran, ok
        }
        m := newMatcher(deps.MatchString, *match, "-test.run")
        tctx := newTestContext(*parallel, m)
+       tctx.deadline = deadline
        fctx := &fuzzContext{
                importPath:       deps.ImportPath,
                readCorpus:       deps.ReadCorpus,

diff --git a/src/testing/testing.go b/src/testing/testing.go
index fa92dbb005c61758f61a8c2e20267d459f2c59cc..581271e74862a13ac42247df332fc7a464e3ed87 100644 (file)
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -1595,7 +1595,7 @@ func (m *M) Run() (code int) {
                deadline := m.startAlarm()
                haveExamples = len(m.examples) > 0
                testRan, testOk := runTests(m.deps.MatchString, m.tests, deadline)
-               fuzzTargetsRan, fuzzTargetsOk := runFuzzTargets(m.deps, m.fuzzTargets)
+               fuzzTargetsRan, fuzzTargetsOk := runFuzzTargets(m.deps, m.fuzzTargets, deadline)
                exampleRan, exampleOk := runExamples(m.deps.MatchString, m.examples)
                m.stopAlarm()
                if !testRan && !exampleRan && !fuzzTargetsRan && *matchBenchmarks == "" && *matchFuzz == "" {