Add quiet mode event coverage

Signed-off-by: Fnuworsu <nuworsufelix49@gmail.com>

Author: Fnuworsu

internal/app/azldev/event_test.go

@@ -0,0 +1,52 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+//nolint:testpackage // testing unexported internal types
+package azldev
+
+import (
+	"io"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func captureStderr(t *testing.T, action func()) string {
+	t.Helper()
+
+	originalStderr := os.Stderr
+	reader, writer, err := os.Pipe()
+	require.NoError(t, err)
+
+	os.Stderr = writer
+
+	action()
+
+	require.NoError(t, writer.Close())
+
+	os.Stderr = originalStderr
+
+	output, err := io.ReadAll(reader)
+	require.NoError(t, err)
+	require.NoError(t, reader.Close())
+
+	return string(output)
+}
+
+func TestEvent_QuietModeSkipsLongRunningAndProgressRendering(t *testing.T) {
+	testEvent := &event{
+		quiet: true,
+	}
+
+	stderrOutput := captureStderr(t, func() {
+		testEvent.SetLongRunning("working")
+		testEvent.SetProgress(1, 10)
+	})
+
+	assert.Empty(t, stderrOutput)
+	assert.Nil(t, testEvent.spinner)
+	assert.False(t, testEvent.initializedProgressBar)
+	assert.Zero(t, testEvent.lastReportedCompletionRatio)
+}