Switch some dy2st UT to eager mode (#41052)

* Switch some dy2st UT to eager mode

* Add UT

python/paddle/fluid/tests/unittests/dygraph_to_static/test_break_continue.py

@@ -262,4 +262,5 @@ class TestOptimBreakInWhile(TestContinueInWhile):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    with fluid.framework._test_eager_guard():
+        unittest.main()

python/paddle/fluid/tests/unittests/dygraph_to_static/test_ifelse.py

@@ -425,4 +425,5 @@ class TestDy2StIfElseRetInt4(TestDy2StIfElseRetInt1):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    with paddle.fluid.framework._test_eager_guard():
+        unittest.main()

python/paddle/fluid/tests/unittests/dygraph_to_static/test_loop.py

@@ -421,4 +421,5 @@ class TestErrorInForLoop(TestTransformForLoop):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    with fluid.framework._test_eager_guard():
+        unittest.main()

python/paddle/fluid/tests/unittests/dygraph_to_static/test_mnist_amp.py

@@ -91,4 +91,5 @@ class TestAMP(TestMNIST):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    with paddle.fluid.framework._test_eager_guard():
+        unittest.main()

python/paddle/fluid/tests/unittests/dygraph_to_static/test_mnist_pure_fp16.py

@@ -108,4 +108,5 @@ class TestPureFP16(TestMNIST):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    with paddle.fluid.framework._test_eager_guard():
+        unittest.main()

python/paddle/fluid/tests/unittests/dygraph_to_static/test_reinforcement_learning.py

@@ -213,4 +213,5 @@ class TestDeclarative(unittest.TestCase):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    with fluid.framework._test_eager_guard():
+        unittest.main()

python/paddle/fluid/tests/unittests/dygraph_to_static/test_yolov3.py

@@ -170,4 +170,5 @@ class TestYolov3(unittest.TestCase):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    with fluid.framework._test_eager_guard():
+        unittest.main()