added timer_provider_tests

test/timer_provider_test.dart

@@ -0,0 +1,43 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:smoke_cess_app/providers/timer_provider.dart';
+
+void main() {
+  test('Timer should start and set started to true', () {
+      final timerProvider = TimerProvider();
+      timerProvider.startTimer(Duration(seconds: 10));
+      expect(timerProvider.started, true);
+  });
+
+  test('Elapsed time should increase and be less than or equal to the duration', () {
+  final timerProvider = TimerProvider();
+  timerProvider.startTimer(Duration(seconds: 10));
+  final initialElapsedSeconds = timerProvider.elapsedSeconds;
+  // Wait for the timer to tick at least once.
+  Future.delayed(Duration(seconds: 2), () {
+    expect(timerProvider.elapsedSeconds, greaterThan(initialElapsedSeconds));
+    expect(timerProvider.elapsedSeconds, lessThanOrEqualTo(10));
+  });
+});
+
+test('Timer should stop and set started to false', () {
+  final timerProvider = TimerProvider();
+  timerProvider.startTimer(Duration(seconds: 10));
+  timerProvider.stopTimer();
+  expect(timerProvider.started, false);
+});
+
+test('Elapsed seconds should be 0 when timer is not running', () {
+  final timerProvider = TimerProvider();
+  expect(timerProvider.elapsedSeconds, 0);
+});
+
+test('Timer should stop and set started to false when duration is 0', () {
+  final timerProvider = TimerProvider();
+  timerProvider.startTimer(Duration(seconds: 0));
+  expect(timerProvider.started, false);
+});
+
+
+}
+