[chore][pkg/stanza] Use mock timers for flaky windows flash tests (#3…

…4128)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
Trying out to mock the actual clock in order to fix flaky tests on
windows.
ref:
#32715 (comment)

**Link to tracking Issue:** <Issue number if applicable>
#32715

**Testing:** <Describe what testing was performed and which tests were
added.>

**Documentation:** <Describe the documentation added.>

---------

Signed-off-by: ChrsMark <chrismarkou92@gmail.com>

pkg/stanza/fileconsumer/internal/reader/reader_test.go

@@ -6,16 +6,17 @@ package reader
 import (
 	"context"
 	"fmt"
-	"runtime"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/jonboulle/clockwork"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/fileconsumer/internal/filetest"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/fileconsumer/internal/fingerprint"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/internal/now"
 )
 
 func TestFileReader_FingerprintUpdated(t *testing.T) {
@@ -189,9 +190,6 @@ func TestFingerprintChangeSize(t *testing.T) {
 }
 
 func TestFlushPeriodEOF(t *testing.T) {
-	if runtime.GOOS == "windows" {
-		t.Skip("Skipping test on Windows; See https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/32715")
-	}
 	tempDir := t.TempDir()
 	temp := filetest.OpenTemp(t, tempDir)
 	// Create a long enough initial token, so the scanner can't read the whole file at once
@@ -209,6 +207,25 @@ func TestFlushPeriodEOF(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, int64(0), r.Offset)
 
+	now.Now = newAlwaysIncreasingClock().Now
+	defer func() { now.Now = time.Now }()
+
 	r.ReadToEnd(context.Background())
 	sink.ExpectTokens(t, content[0:aContentLength], []byte{'b'})
 }
+
+// Clock where Now() always returns a greater value than the previous return value
+type alwaysIncreasingClock struct {
+	clockwork.FakeClock
+}
+
+func newAlwaysIncreasingClock() alwaysIncreasingClock {
+	return alwaysIncreasingClock{
+		FakeClock: clockwork.NewFakeClock(),
+	}
+}
+
+func (c alwaysIncreasingClock) Now() time.Time {
+	c.FakeClock.Advance(time.Nanosecond)
+	return c.FakeClock.Now()
+}

pkg/stanza/flush/flush.go

@@ -6,6 +6,8 @@ package flush // import "github.com/open-telemetry/opentelemetry-collector-contr
 import (
 	"bufio"
 	"time"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/internal/now"
 )
 
 type State struct {
@@ -40,7 +42,7 @@ func (s *State) Func(splitFunc bufio.SplitFunc, period time.Duration) bufio.Spli
 
 		// If there's a token, return it
 		if token != nil {
-			s.LastDataChange = time.Now()
+			s.LastDataChange = now.Now()
 			s.LastDataLength = 0
 			return advance, token, err
 		}
@@ -53,14 +55,14 @@ func (s *State) Func(splitFunc bufio.SplitFunc, period time.Duration) bufio.Spli
 
 		// We're seeing new data so postpone the next flush
 		if len(data) > s.LastDataLength {
-			s.LastDataChange = time.Now()
+			s.LastDataChange = now.Now()
 			s.LastDataLength = len(data)
 			return 0, nil, nil
 		}
 
 		// Flush timed out
 		if time.Since(s.LastDataChange) > period {
-			s.LastDataChange = time.Now()
+			s.LastDataChange = now.Now()
 			s.LastDataLength = 0
 			return len(data), data, nil
 		}
@@ -72,6 +74,6 @@ func (s *State) Func(splitFunc bufio.SplitFunc, period time.Duration) bufio.Spli
 
 // Deprecated: [v0.88.0] Use WithFunc instead.
 func WithPeriod(splitFunc bufio.SplitFunc, period time.Duration) bufio.SplitFunc {
-	s := &State{LastDataChange: time.Now()}
+	s := &State{LastDataChange: now.Now()}
 	return s.Func(splitFunc, period)
 }

pkg/stanza/go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/expr-lang/expr v1.16.9
 	github.com/fsnotify/fsnotify v1.7.0
 	github.com/goccy/go-json v0.10.3
+	github.com/jonboulle/clockwork v0.4.0
 	github.com/jpillora/backoff v1.0.0
 	github.com/json-iterator/go v1.1.12
 	github.com/leodido/go-syslog/v4 v4.1.0

pkg/stanza/internal/now/now.go

@@ -0,0 +1,8 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package now // import "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/internal/now"
+
+import "time"
+
+var Now = time.Now