testing: show in-progress tests upon SIGINT

Because of parallel tests, which have stalled executions, the RUN
output of a test can be much earlier than its completion output resulting
in hard-to-read verbose output.

The tests are displayed in the order in which the output shows
that they began, to make it easy to line up with the "RUN" output.
Similarly, the definitions of when tests begin and complete is
determined by when RUN and FAIL/SKIP/PASS are output since the
focus of this code is on enhancing readability.

Fixes #19397

Change-Id: I4d0ca3fd268b620484e7a190117f79a33b3dc461
Reviewed-on: https://go-review.googlesource.com/44352
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/testing/testing.go

@@ -224,13 +224,16 @@ import (
 	"internal/race"
 	"io"
 	"os"
+	"os/signal"
 	"runtime"
 	"runtime/debug"
 	"runtime/trace"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
 	"sync/atomic"
+	"syscall"
 	"time"
 )
 
@@ -269,6 +272,10 @@ var (
 	haveExamples bool // are there examples?
 
 	cpuList []int
+
+	inProgressMu       sync.Mutex // guards this group of fields
+	inProgressRegistry = make(map[string]int)
+	inProgressIdx      int
 )
 
 // common holds the elements common between T and B and
@@ -778,9 +785,12 @@ func (t *T) Run(name string, f func(t *T)) bool {
 		root := t.parent
 		for ; root.parent != nil; root = root.parent {
 		}
+		inProgressMu.Lock()
 		root.mu.Lock()
+		t.registerInProgress()
 		fmt.Fprintf(root.w, "=== RUN   %s\n", t.name)
 		root.mu.Unlock()
+		inProgressMu.Unlock()
 	}
 	// Instead of reducing the running count of this test before calling the
 	// tRunner and increasing it afterwards, we rely on tRunner keeping the
@@ -942,6 +952,11 @@ func (t *T) report() {
 	}
 	dstr := fmtDuration(t.duration)
 	format := "--- %s: %s (%s)\n"
+
+	inProgressMu.Lock()
+	defer inProgressMu.Unlock()
+	defer t.registerComplete()
+
 	if t.Failed() {
 		t.flushToParent(format, "FAIL", t.name, dstr)
 	} else if t.chatty {
@@ -953,6 +968,39 @@ func (t *T) report() {
 	}
 }
 
+func (t *T) registerInProgress() {
+	if !t.chatty {
+		return
+	}
+	inProgressRegistry[t.name] = inProgressIdx
+	inProgressIdx++
+}
+
+func (t *T) registerComplete() {
+	if !t.chatty {
+		return
+	}
+	delete(inProgressRegistry, t.name)
+}
+
+func reportTestsInProgress() {
+	if len(inProgressRegistry) == 0 {
+		return
+	}
+	idxToName := make(map[int]string)
+	var indexes []int
+	for name, idx := range inProgressRegistry {
+		idxToName[idx] = name
+		indexes = append(indexes, idx)
+	}
+	sort.Ints(indexes)
+	var namesInOrder []string
+	for _, idx := range indexes {
+		namesInOrder = append(namesInOrder, idxToName[idx])
+	}
+	fmt.Printf("\ntests in progress: %s\n", strings.Join(namesInOrder, ", "))
+}
+
 func listTests(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) {
 	if _, err := matchString(*matchList, "non-empty"); err != nil {
 		fmt.Fprintf(os.Stderr, "testing: invalid regexp in -test.list (%q): %s\n", *matchList, err)
@@ -1056,6 +1104,24 @@ func (m *M) before() {
 		fmt.Fprintf(os.Stderr, "testing: cannot use -test.coverprofile because test binary was not built with coverage enabled\n")
 		os.Exit(2)
 	}
+	if Verbose() {
+		sigCh := make(chan os.Signal, 1)
+		signal.Notify(sigCh, os.Interrupt)
+		go func() {
+			<-sigCh
+			signal.Stop(sigCh)
+			inProgressMu.Lock()
+			reportTestsInProgress()
+			inProgressMu.Unlock()
+			proc, err := os.FindProcess(syscall.Getpid())
+			if err == nil {
+				err = proc.Signal(os.Interrupt)
+			}
+			if err != nil {
+				os.Exit(2)
+			}
+		}()
+	}
 }
 
 // after runs after all testing.