One branch recursion

datastructures/recur.go

@@ -0,0 +1,9 @@
+package datastructures
+
+func Factorial(n int) int {
+	if n < 1 {
+		return 1
+	}
+
+	return n * Factorial(n-1)
+}

datastructures/recur_test.go

@@ -0,0 +1,38 @@
+package datastructures
+
+import "testing"
+
+func TestFactorial(t *testing.T) {
+
+	cases := []struct {
+		Name     string
+		Input    int
+		Expected int
+	}{
+		{
+			"Factorial of 5",
+			5,
+			120,
+		},
+		{
+			"Factorial of 10",
+			10,
+			3628800,
+		},
+		{
+			"Factorial of 12",
+			12,
+			479001600,
+		},
+	}
+
+	for _, test := range cases {
+		t.Run(test.Name, func(t *testing.T) {
+			got := Factorial(test.Input)
+
+			if got != test.Expected {
+				t.Errorf("Error got: %d want: %d", got, test.Expected)
+			}
+		})
+	}
+}