add test functions

cpp_template/calc.cpp

@@ -0,0 +1,11 @@
+#include <math.h>
+ 
+// Get the Square root of a number. 
+double squareRoot(const double a) 
+    {
+    double b = sqrt(a);
+    if(b != b) // NaN check
+        { return -1.0; }
+    else
+        { return sqrt(a); }
+    }

cpp_template/calc_test.cpp

@@ -0,0 +1,22 @@
+#include "calc.cpp"
+#include <gtest/gtest.h>
+ 
+TEST(SquareRootTest, PositiveNos) 
+    { 
+    ASSERT_EQ(6, squareRoot(36.0));
+    ASSERT_EQ(18.0, squareRoot(324.0));
+    ASSERT_EQ(25.4, squareRoot(645.16));
+    ASSERT_EQ(0, squareRoot(0.0));
+    }
+ 
+TEST(SquareRootTest, NegativeNos) 
+    {
+    ASSERT_EQ(-1.0, squareRoot(-15.0));
+    ASSERT_EQ(-1.0, squareRoot(-0.2));
+    }
+ 
+int main(int argc, char **argv) 
+    {
+    testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+    }