Test

pkg/main.go

@@ -0,0 +1,14 @@
+package main
+
+import "fmt"
+
+func Calculate(x int) (result int) {
+	result = x + 2
+	return result
+}
+
+func main() {
+	fmt.Println("Go Calculate")
+	result := Calculate(2)
+	fmt.Println(result)
+}

pkg/main_test.go

@@ -0,0 +1,26 @@
+package main
+
+import "testing"
+
+func TestCalculate(t *testing.T) {
+	if Calculate(2) != 4 {
+		t.Error("Expected 2 + 2 equal 4")
+	}
+}
+
+func TestTableCalculate(t *testing.T) {
+	var tests = []struct {
+		input    int
+		expected int
+	}{
+		{2, 4},
+		{-3, -1},
+		{0, 2},
+		{99989988, 99989990},
+	}
+	for _, test := range tests {
+		if output := Calculate(test.input); output != test.expected {
+			t.Errorf("Test Failed: %d, inputted: %d expected, recieved: %d", test.input, test.expected, output)
+		}
+	}
+}