chore: import upstream snapshot with attribution

test/op/SoftplusTest.cpp

@@ -0,0 +1,41 @@
+//
+//  SoftplusTest.cpp
+//  MNNTests
+//
+//  Created by MNN on 2019/12/26.
+//  Copyright © 2018, Alibaba Group Holding Limited
+//
+
+#include <MNN/expr/Expr.hpp>
+#include <MNN/expr/ExprCreator.hpp>
+#include "MNNTestSuite.h"
+#include "TestUtils.h"
+
+using namespace MNN::Express;
+class SoftplusTest : public MNNTestCase {
+public:
+    virtual ~SoftplusTest() = default;
+    virtual bool run(int precision) {
+        auto input = _Input(
+            {
+                4,
+            },
+            NCHW);
+        input->setName("input_tensor");
+        // set input data
+        const float inpudata[] = {-1.0, -2.0, 3.0, 4.0};
+        auto inputPtr          = input->writeMap<float>();
+        memcpy(inputPtr, inpudata, 4 * sizeof(float));
+        input->unMap();
+        auto output                             = _Softplus(input);
+        const std::vector<float> expectedOutput = {0.31326166, 0.12692805, 3.0485873, 4.01815};
+        auto gotOutput                          = output->readMap<float>();
+        float errorScale = precision <= MNN::BackendConfig::Precision_High ? 1 : 100;
+        if (!checkVectorByRelativeError<float>(gotOutput, expectedOutput.data(), 4, 0.0001 * errorScale)) {
+            MNN_ERROR("SoftplusTest test failed!\n");
+            return false;
+        }
+        return true;
+    }
+};
+MNNTestSuiteRegister(SoftplusTest, "op/softplus");