diff --git a/tests/st/explainer/__init__.py b/tests/st/explainer/__init__.py
new file mode 100644
index 0000000000..142283a621
--- /dev/null
+++ b/tests/st/explainer/__init__.py
@@ -0,0 +1,15 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Initialization of tests of explanation related classes."""
diff --git a/tests/st/explainer/benchmark/__init__.py b/tests/st/explainer/benchmark/__init__.py
new file mode 100644
index 0000000000..b27beebb79
--- /dev/null
+++ b/tests/st/explainer/benchmark/__init__.py
@@ -0,0 +1,15 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Initialization of tests of mindspore.explainer.benchmark."""
diff --git a/tests/st/explainer/benchmark/_attribution/__init__.py b/tests/st/explainer/benchmark/_attribution/__init__.py
new file mode 100644
index 0000000000..5317b762dc
--- /dev/null
+++ b/tests/st/explainer/benchmark/_attribution/__init__.py
@@ -0,0 +1,15 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Initialization of tests of in mindspore.explainer.benchmark."""
diff --git a/tests/st/explainer/benchmark/_attribution/test_localization.py b/tests/st/explainer/benchmark/_attribution/test_localization.py
new file mode 100644
index 0000000000..d456c1132f
--- /dev/null
+++ b/tests/st/explainer/benchmark/_attribution/test_localization.py
@@ -0,0 +1,134 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Tests of Localization of mindspore.explainer.benchmark."""
+
+from unittest.mock import patch
+
+import numpy as np
+import pytest
+
+import mindspore as ms
+from mindspore import context
+from mindspore import nn
+from mindspore.explainer.benchmark import Localization
+from mindspore.explainer.explanation import Gradient
+
+
+context.set_context(mode=context.PYNATIVE_MODE)
+
+H, W = 4, 4
+SALIENCY = ms.Tensor(np.random.rand(1, 1, H, W), ms.float32)
+
+
+class CustomNet(nn.Cell):
+    """Simple net for unit test."""
+
+    def __init__(self):
+        super().__init__()
+
+    def construct(self, _):
+        return ms.Tensor([[0.1, 0.9]], ms.float32)
+
+
+def mock_gradient_call(_, inputs, targets):
+    del inputs, targets
+    return SALIENCY
+
+
+class TestLocalization:
+    """Test on Localization."""
+
+    def setup_method(self):
+        self.net = CustomNet()
+        self.data = ms.Tensor(np.random.rand(1, 1, H, W), ms.float32)
+        self.target = 1
+
+        masks_np = np.zeros((1, 1, H, W))
+        masks_np[:, :, 1:3, 1:3] = 1
+        self.masks_np = masks_np
+        self.masks = ms.Tensor(masks_np, ms.float32)
+
+        self.explainer = Gradient(self.net)
+        self.saliency_gt = mock_gradient_call(self.explainer, self.data, self.target)
+        self.num_class = 2
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_pointing_game(self):
+        """Test case for `metric="PointingGame"` without input saliency."""
+        with patch.object(Gradient, "__call__", mock_gradient_call):
+            max_pos = np.argmax(abs(self.saliency_gt.asnumpy().flatten()))
+            x_gt, y_gt = max_pos // W, max_pos % W
+            res_gt = self.masks_np[0, 0, x_gt, y_gt]
+
+            pg = Localization(self.num_class, metric="PointingGame")
+            pg._metric_arg = 1  # make the tolerance smaller to simplify the test
+
+            res = pg.evaluate(self.explainer, self.data, targets=self.target, mask=self.masks)
+        assert np.max(np.abs(np.array([res_gt]) - res)) < 1e-5
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_iosr(self):
+        """Test case for `metric="IoSR"` without input saliency."""
+        with patch.object(Gradient, "__call__", mock_gradient_call):
+            threshold = 0.5
+            max_val = np.max(self.saliency_gt.asnumpy())
+            sr = (self.saliency_gt.asnumpy() > (max_val * threshold)).astype(int)
+            res_gt = np.sum(sr * self.masks_np) / (np.sum(sr).clip(1e-10))
+
+            iosr = Localization(self.num_class, metric="IoSR")
+            iosr._metric_arg = threshold
+
+            res = iosr.evaluate(self.explainer, self.data, targets=self.target, mask=self.masks)
+
+        assert np.allclose(np.array([res_gt]), res)
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_pointing_game_with_saliency(self):
+        """Test metric PointingGame with input saliency."""
+        max_pos = np.argmax(abs(self.saliency_gt.asnumpy().flatten()))
+        x_gt, y_gt = max_pos // W, max_pos % W
+        res_gt = self.masks_np[0, 0, x_gt, y_gt]
+
+        pg = Localization(self.num_class, metric="PointingGame")
+        pg._metric_arg = 1  # make the tolerance smaller to simplify the test
+
+        res = pg.evaluate(self.explainer, self.data, targets=self.target, mask=self.masks, saliency=self.saliency_gt)
+        assert np.allclose(np.array([res_gt]), res)
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_iosr_with_saliency(self):
+        """Test metric IoSR with input saliency map."""
+        threshold = 0.5
+        max_val = np.max(self.saliency_gt.asnumpy())
+        sr = (self.saliency_gt.asnumpy() > (max_val * threshold)).astype(int)
+        res_gt = np.sum(sr * self.masks_np) / (np.sum(sr).clip(1e-10))
+
+        iosr = Localization(self.num_class, metric="IoSR")
+
+        res = iosr.evaluate(self.explainer, self.data, targets=self.target, mask=self.masks, saliency=self.saliency_gt)
+
+        assert np.allclose(np.array([res_gt]), res)
diff --git a/tests/st/explainer/explanation/__init__.py b/tests/st/explainer/explanation/__init__.py
new file mode 100644
index 0000000000..b56c349088
--- /dev/null
+++ b/tests/st/explainer/explanation/__init__.py
@@ -0,0 +1,15 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Initialization of tests of mindspore.explainer.explanation."""
diff --git a/tests/st/explainer/explanation/_attribution/__init__.py b/tests/st/explainer/explanation/_attribution/__init__.py
new file mode 100644
index 0000000000..aa25136448
--- /dev/null
+++ b/tests/st/explainer/explanation/_attribution/__init__.py
@@ -0,0 +1,15 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Initialization of tests of explainers of mindspore.explainer.explanation."""
diff --git a/tests/st/explainer/explanation/_attribution/_backprop/__init__.py b/tests/st/explainer/explanation/_attribution/_backprop/__init__.py
new file mode 100644
index 0000000000..80f20deaa6
--- /dev/null
+++ b/tests/st/explainer/explanation/_attribution/_backprop/__init__.py
@@ -0,0 +1,15 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Initialization of tests of back-propagation based explainers."""
diff --git a/tests/st/explainer/explanation/_attribution/_backprop/test_gradcam.py b/tests/st/explainer/explanation/_attribution/_backprop/test_gradcam.py
new file mode 100644
index 0000000000..e7b71937c5
--- /dev/null
+++ b/tests/st/explainer/explanation/_attribution/_backprop/test_gradcam.py
@@ -0,0 +1,104 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Tests of GradCAM of mindspore.explainer.explanation."""
+
+from unittest.mock import patch
+
+import numpy as np
+import pytest
+
+import mindspore as ms
+from mindspore import context
+import mindspore.ops.operations as op
+from mindspore import nn
+from mindspore.explainer.explanation import GradCAM
+from mindspore.explainer.explanation._attribution._backprop.gradcam import _gradcam_aggregation as aggregation
+
+
+context.set_context(mode=context.PYNATIVE_MODE)
+
+
+class SimpleAvgLinear(nn.Cell):
+    """Simple linear model for the unit test."""
+
+    def __init__(self):
+        super().__init__()
+        self.avgpool = nn.AvgPool2d(2, 2)
+        self.flatten = nn.Flatten()
+        self.fc2 = nn.Dense(4, 3)
+
+    def construct(self, x):
+        x = self.avgpool(x)
+        x = self.flatten(x)
+        return self.fc2(x)
+
+
+def resize_fn(attributions, inputs, mode):
+    """Mocked resize function for test."""
+    del inputs, mode
+    return attributions
+
+
+class TestGradCAM:
+    """Test GradCAM."""
+
+    def setup_method(self):
+        self.net = SimpleAvgLinear()
+        self.data = ms.Tensor(np.random.random(size=(1, 1, 4, 4)), ms.float32)
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_gradcam_attribution(self):
+        """Test __call__ method in GradCAM."""
+        with patch.object(GradCAM, "_resize_fn", side_effect=resize_fn):
+            layer = "avgpool"
+
+            gradcam = GradCAM(self.net, layer=layer)
+
+            data = ms.Tensor(np.random.random(size=(1, 1, 4, 4)), ms.float32)
+            num_classes = 3
+            activation = self.net.avgpool(data)
+            reshape = op.Reshape()
+            for x in range(num_classes):
+                target = ms.Tensor([x], ms.int32)
+                attribution = gradcam(data, target)
+                # intermediate grad should be reshape of weight of fc2
+                intermediate_grad = self.net.fc2.weight.data[x]
+                reshaped = reshape(intermediate_grad, (1, 1, 2, 2))
+                gap_grad = self.net.avgpool(reshaped)
+                res = aggregation(gap_grad * activation)
+                assert np.allclose(res.asnumpy(), attribution.asnumpy(), atol=1e-5, rtol=1e-3)
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_layer_default(self):
+        """Test layer argument of GradCAM."""
+        with patch.object(GradCAM, "_resize_fn", side_effect=resize_fn):
+            gradcam = GradCAM(self.net)
+            num_classes = 3
+            sum_ = op.ReduceSum()
+            for x in range(num_classes):
+                target = ms.Tensor([x], ms.int32)
+                attribution = gradcam(self.data, target)
+
+                # intermediate_grad should be reshape of weight of fc2
+                intermediate_grad = self.net.fc2.weight.data[x]
+                avggrad = float(sum_(intermediate_grad).asnumpy() / 16)
+                res = aggregation(avggrad * self.data)
+                assert np.allclose(res.asnumpy(), attribution.asnumpy(), atol=1e-5, rtol=1e-3)
diff --git a/tests/st/explainer/explanation/_attribution/_backprop/test_gradient.py b/tests/st/explainer/explanation/_attribution/_backprop/test_gradient.py
new file mode 100644
index 0000000000..a71e7fa049
--- /dev/null
+++ b/tests/st/explainer/explanation/_attribution/_backprop/test_gradient.py
@@ -0,0 +1,74 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Tests of Gradient of mindspore.explainer.explanation."""
+
+import numpy as np
+import pytest
+
+import mindspore as ms
+from mindspore import context
+import mindspore.ops.operations as P
+from mindspore import nn
+from mindspore.explainer.explanation import Gradient
+
+
+context.set_context(mode=context.PYNATIVE_MODE)
+
+
+class SimpleLinear(nn.Cell):
+    """Simple linear model for the unit test."""
+
+    def __init__(self):
+        super().__init__()
+        self.relu = nn.ReLU()
+        self.flatten = nn.Flatten()
+        self.fc2 = nn.Dense(16, 3)
+
+    def construct(self, x):
+        x = self.relu(x)
+        x = self.flatten(x)
+        return self.fc2(x)
+
+
+class TestGradient:
+    """Test Gradient."""
+
+    def setup_method(self):
+        """Setup the test case."""
+        self.net = SimpleLinear()
+        self.relu = P.ReLU()
+        self.abs_ = P.Abs()
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_gradient(self):
+        """Test gradient __call__ function."""
+        data = (ms.Tensor(np.random.random(size=(1, 1, 4, 4)),
+                          ms.float32) - 0.5) * 2
+        explainer = Gradient(self.net)
+
+        num_classes = 3
+        reshape = P.Reshape()
+        for x in range(num_classes):
+            target = ms.Tensor([x], ms.int32)
+
+            attribution = explainer(data, target)
+
+            # intermediate_grad should be reshape of weight of fc2
+            grad = self.net.fc2.weight.data[x]
+            grad = self.abs_(reshape(grad, (1, 1, 4, 4)) * (self.abs_(self.relu(data) / data)))
+            assert np.allclose(grad.asnumpy(), attribution.asnumpy())
diff --git a/tests/st/explainer/explanation/_attribution/_backprop/test_modified_relu.py b/tests/st/explainer/explanation/_attribution/_backprop/test_modified_relu.py
new file mode 100644
index 0000000000..f365bc32d4
--- /dev/null
+++ b/tests/st/explainer/explanation/_attribution/_backprop/test_modified_relu.py
@@ -0,0 +1,92 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Tests of Deconvolution and GuidedBackprop of mindspore.explainer.explanation."""
+
+import numpy as np
+import pytest
+
+import mindspore as ms
+import mindspore.ops.operations as P
+from mindspore import context
+from mindspore import nn
+from mindspore.explainer.explanation import Deconvolution, GuidedBackprop
+
+
+context.set_context(mode=context.PYNATIVE_MODE)
+
+
+class SimpleLinear(nn.Cell):
+    """Simple linear model for the unit test."""
+
+    def __init__(self):
+        super().__init__()
+        self.relu = nn.ReLU()
+        self.flatten = nn.Flatten()
+        self.fc2 = nn.Dense(16, 3)
+
+    def construct(self, x):
+        x = self.relu(x)
+        x = self.flatten(x)
+        return self.fc2(x)
+
+
+class TestModifiedReLU:
+    """Test on modified_relu module, Deconvolution and GuidedBackprop specifically."""
+    def setup_method(self):
+        """Setup the test case."""
+        self.net = SimpleLinear()
+        self.relu = P.ReLU()
+        self.abs_ = P.Abs()
+        self.reshape = P.Reshape()
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_deconvolution(self):
+        """Test deconvolution attribution."""
+        data = (ms.Tensor(np.random.random(size=(1, 1, 4, 4)),
+                          ms.float32) - 0.5) * 2
+        deconv = Deconvolution(self.net)
+
+        num_classes = 3
+        for x in range(num_classes):
+            target = ms.Tensor([x], ms.int32)
+
+            attribution = deconv(data, target)
+
+            # intermediate_grad should be reshape of weight of fc2
+            grad = self.net.fc2.weight.data[x]
+            grad = self.abs_(self.relu(self.reshape(grad, (1, 1, 4, 4))))
+            assert np.allclose(attribution.asnumpy(), grad.asnumpy())
+
+    def test_guided_backprop(self):
+        """Test deconvolution attribution."""
+        data = (ms.Tensor(np.random.random(size=(1, 1, 4, 4)),
+                          ms.float32) - 0.5) * 2
+        explainer = GuidedBackprop(self.net)
+
+        num_classes = 3
+        for x in range(num_classes):
+            target = ms.Tensor([x], ms.int32)
+
+            attribution = explainer(data, target)
+
+            # intermediate_grad should be reshape of weight of fc2
+            grad = self.net.fc2.weight.data[x]
+            grad = self.reshape(grad, (1, 1, 4, 4))
+            guided_grad = self.abs_(self.relu(grad * (self.abs_(self.relu(data) / data))))
+
+            assert np.allclose(guided_grad.asnumpy(), attribution.asnumpy())
diff --git a/tests/st/explainer/test_runner.py b/tests/st/explainer/test_runner.py
new file mode 100644
index 0000000000..8577a2ae24
--- /dev/null
+++ b/tests/st/explainer/test_runner.py
@@ -0,0 +1,200 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Tests on mindspore.explainer.ImageClassificationRunner."""
+
+import os
+import shutil
+from random import random
+from unittest.mock import patch
+
+import numpy as np
+import pytest
+from PIL import Image
+
+from mindspore import context
+import mindspore as ms
+import mindspore.nn as nn
+from mindspore.dataset import GeneratorDataset
+from mindspore.explainer import ImageClassificationRunner
+from mindspore.explainer._image_classification_runner import _normalize
+from mindspore.explainer.benchmark import Faithfulness
+from mindspore.explainer.explanation import Gradient
+from mindspore.train.summary import SummaryRecord
+
+CONST = random()
+NUMDATA = 2
+
+context.set_context(mode=context.PYNATIVE_MODE)
+
+def image_label_bbox_generator():
+    for i in range(NUMDATA):
+        image = np.arange(i, i + 16 * 3).reshape((3, 4, 4)) / 50
+        label = np.array(i)
+        bbox = np.array([1, 1, 2, 2])
+        yield (image, label, bbox)
+
+
+class SimpleNet(nn.Cell):
+    """
+    Simple model for the unit test.
+    """
+
+    def __init__(self):
+        super(SimpleNet, self).__init__()
+        self.reshape = ms.ops.operations.Reshape()
+
+    def construct(self, x):
+        prob = ms.Tensor([0.1, 0.9], ms.float32)
+        prob = self.reshape(prob, (1, 2))
+        return prob
+
+
+class ActivationFn(nn.Cell):
+    """
+    Simple activation function for unit test.
+    """
+
+    def __init__(self):
+        super(ActivationFn, self).__init__()
+
+    def construct(self, x):
+        return x
+
+
+def mock_gradient_call(_, inputs, targets):
+    return inputs[:, 0:1, :, :]
+
+
+def mock_faithfulness_evaluate(_, explainer, inputs, targets, saliency):
+    return CONST * targets
+
+
+def mock_make_rgba(array):
+    return array.asnumpy()
+
+
+class TestRunner:
+    """Test on Runner."""
+
+    def setup_method(self):
+        self.dataset = GeneratorDataset(image_label_bbox_generator, ["image", "label", "bbox"])
+        self.labels = ["label_{}".format(i) for i in range(2)]
+        self.network = SimpleNet()
+        self.summary_dir = "summary_test_temp"
+        self.explainer = [Gradient(self.network)]
+        self.activation_fn = ActivationFn()
+        self.benchmarkers = [Faithfulness(num_labels=len(self.labels),
+                                          metric="NaiveFaithfulness",
+                                          activation_fn=self.activation_fn)]
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_run_saliency_no_benchmark(self):
+        """Test case when argument benchmarkers is not parsed."""
+        res = []
+        runner = ImageClassificationRunner(summary_dir=self.summary_dir, data=(self.dataset, self.labels),
+                                           network=self.network, activation_fn=self.activation_fn)
+
+        def mock_summary_add_value(_, plugin, name, value):
+            res.append((plugin, name, value))
+
+        with patch.object(SummaryRecord, "add_value", mock_summary_add_value), \
+             patch.object(Gradient, "__call__", mock_gradient_call):
+            runner.register_saliency(self.explainer)
+            runner.run()
+
+        # test on meta data
+        idx = 0
+        assert res[idx][0] == "explainer"
+        assert res[idx][1] == "metadata"
+        assert res[idx][2].metadata.label == self.labels
+        assert res[idx][2].metadata.explain_method == ["Gradient"]
+
+        # test on inference data
+        for i in range(NUMDATA):
+            idx += 1
+            data_np = np.arange(i, i + 3 * 16).reshape((3, 4, 4)) / 50
+            assert res[idx][0] == "explainer"
+            assert res[idx][1] == "sample"
+            assert res[idx][2].sample_id == i
+            original_path = os.path.join(self.summary_dir, res[idx][2].image_path)
+            with open(original_path, "rb") as f:
+                image_data = np.asarray(Image.open(f)) / 255.0
+            original_image = _normalize(np.transpose(data_np, [1, 2, 0]))
+            assert np.allclose(image_data, original_image, rtol=3e-2, atol=3e-2)
+
+            idx += 1
+            assert res[idx][0] == "explainer"
+            assert res[idx][1] == "inference"
+            assert res[idx][2].sample_id == i
+            assert res[idx][2].ground_truth_label == [i]
+
+            diff = np.array(res[idx][2].inference.ground_truth_prob) - np.array([[0.1, 0.9][i]])
+            assert np.max(np.abs(diff)) < 1e-6
+            assert res[idx][2].inference.predicted_label == [1]
+            diff = np.array(res[idx][2].inference.predicted_prob) - np.array([0.9])
+            assert np.max(np.abs(diff)) < 1e-6
+
+        # test on explanation data
+        for i in range(NUMDATA):
+            idx += 1
+            data_np = np.arange(i, i + 3 * 16).reshape((3, 4, 4)) / 50
+            saliency_np = data_np[0, :, :]
+            assert res[idx][0] == "explainer"
+            assert res[idx][1] == "explanation"
+            assert res[idx][2].sample_id == i
+            assert res[idx][2].explanation[0].explain_method == "Gradient"
+
+            assert res[idx][2].explanation[0].label in [i, 1]
+
+            heatmap_path = os.path.join(self.summary_dir, res[idx][2].explanation[0].heatmap_path)
+            assert os.path.exists(heatmap_path)
+
+            with open(heatmap_path, "rb") as f:
+                heatmap_data = np.asarray(Image.open(f)) / 255.0
+            heatmap_image = _normalize(saliency_np)
+            assert np.allclose(heatmap_data, heatmap_image, atol=3e-2, rtol=3e-2)
+
+    @pytest.mark.level0
+    @pytest.mark.platform_arm_ascend_training
+    @pytest.mark.platform_x86_ascend_training
+    @pytest.mark.env_onecard
+    def test_run_saliency_with_benchmark(self):
+        """Test case when argument benchmarkers is parsed."""
+        res = []
+
+        def mock_summary_add_value(_, plugin, name, value):
+            res.append((plugin, name, value))
+
+        runner = ImageClassificationRunner(summary_dir=self.summary_dir, data=(self.dataset, self.labels),
+                                           network=self.network, activation_fn=self.activation_fn)
+
+        with patch.object(SummaryRecord, "add_value", mock_summary_add_value), \
+             patch.object(Gradient, "__call__", mock_gradient_call), \
+             patch.object(Faithfulness, "evaluate", mock_faithfulness_evaluate):
+            runner.register_saliency(self.explainer, self.benchmarkers)
+            runner.run()
+
+        idx = 3 * NUMDATA + 1  # start index of benchmark data
+        assert res[idx][0] == "explainer"
+        assert res[idx][1] == "benchmark"
+        assert abs(res[idx][2].benchmark[0].total_score - 2 / 3 * CONST) < 1e-6
+        diff = np.array(res[idx][2].benchmark[0].label_score) - np.array([i * CONST for i in range(NUMDATA)])
+        assert np.max(np.abs(diff)) < 1e-6
+
+    def teardown_method(self):
+        shutil.rmtree(self.summary_dir)
diff --git a/tests/st/explainer/test_utils.py b/tests/st/explainer/test_utils.py
new file mode 100644
index 0000000000..b8e4d8c9e1
--- /dev/null
+++ b/tests/st/explainer/test_utils.py
@@ -0,0 +1,119 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+"""Unit test on mindspore.explainer._utils."""
+
+import numpy as np
+import pytest
+
+import mindspore as ms
+import mindspore.nn as nn
+
+from mindspore.explainer._utils import (
+    ForwardProbe,
+    rank_pixels,
+    retrieve_layer,
+    retrieve_layer_by_name)
+from mindspore.explainer.explanation._attribution._backprop.backprop_utils import GradNet, get_bp_weights
+
+
+class CustomNet(nn.Cell):
+    """Simple net for test."""
+
+    def __init__(self):
+        super(CustomNet, self).__init__()
+        self.fc1 = nn.Dense(10, 10)
+        self.fc2 = nn.Dense(10, 10)
+        self.fc3 = nn.Dense(10, 10)
+        self.fc4 = nn.Dense(10, 10)
+
+    def construct(self, inputs):
+        out = self.fc1(inputs)
+        out = self.fc2(out)
+        out = self.fc3(out)
+        out = self.fc4(out)
+        return out
+
+
+@pytest.mark.level0
+@pytest.mark.platform_arm_ascend_training
+@pytest.mark.platform_x86_ascend_training
+@pytest.mark.env_onecard
+def test_rank_pixels():
+    """Test on rank_pixels."""
+    saliency = np.array([[4., 3., 1.], [5., 9., 1.]])
+    descending_target = np.array([[0, 1, 2], [1, 0, 2]])
+    ascending_target = np.array([[2, 1, 0], [1, 2, 0]])
+    descending_rank = rank_pixels(saliency)
+    ascending_rank = rank_pixels(saliency, descending=False)
+    assert (descending_rank - descending_target).any() == 0
+    assert (ascending_rank - ascending_target).any() == 0
+
+
+@pytest.mark.level0
+@pytest.mark.platform_arm_ascend_training
+@pytest.mark.platform_x86_ascend_training
+@pytest.mark.env_onecard
+def test_retrieve_layer_by_name():
+    """Test on rank_pixels."""
+    model = CustomNet()
+    target_layer_name = 'fc3'
+    target_layer = retrieve_layer_by_name(model, target_layer_name)
+
+    assert target_layer is model.fc3
+
+
+@pytest.mark.level0
+@pytest.mark.platform_arm_ascend_training
+@pytest.mark.platform_x86_ascend_training
+@pytest.mark.env_onecard
+def test_retrieve_layer_by_name_no_name():
+    """Test on retrieve layer."""
+    model = CustomNet()
+    target_layer = retrieve_layer_by_name(model, '')
+
+    assert target_layer is model
+
+
+@pytest.mark.level0
+@pytest.mark.platform_arm_ascend_training
+@pytest.mark.platform_x86_ascend_training
+@pytest.mark.env_onecard
+def test_forward_probe():
+    """Test case for ForwardProbe."""
+    model = CustomNet()
+    model.set_grad()
+    inputs = np.random.random((1, 10))
+    inputs = ms.Tensor(inputs, ms.float32)
+    gt_activation = model.fc3(model.fc2(model.fc1(inputs))).asnumpy()
+
+    targets = 1
+    weights = get_bp_weights(model, inputs, targets=targets)
+
+    gradnet = GradNet(model)
+    grad_before_probe = gradnet(inputs, weights).asnumpy()
+
+    # Probe forward tensor
+    saliency_layer = retrieve_layer(model, 'fc3')
+
+    with ForwardProbe(saliency_layer) as probe:
+        grad_after_probe = gradnet(inputs, weights).asnumpy()
+        activation = probe.value.asnumpy()
+
+    grad_after_unprobe = gradnet(inputs, weights).asnumpy()
+
+    assert np.array_equal(gt_activation, activation)
+    assert np.array_equal(grad_before_probe, grad_after_probe)
+    assert np.array_equal(grad_before_probe, grad_after_unprobe)
+    assert probe.value is None