Add task6 in go

Author: Holger Lösken

src/go/t6/s1.go

@@ -0,0 +1,26 @@
+package main
+
+import "strconv"
+
+func Fib(number int) int  {
+	if number < 0 {
+		return -1
+	}
+
+	if number <= 1 {
+		return number
+	}
+
+	return Fib(number-1) + Fib(number-2)
+}
+
+func Fibonacci(number int) (int, error) {
+	result := Fib(number)
+	s := strconv.Itoa(result)
+
+	if len(s) > 6 {
+		return strconv.Atoi(s[len(s)-6:])
+	}
+
+	return strconv.Atoi(s)
+}

src/go/t6/s1_test.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestFibonacci(t *testing.T) {
+	type test struct {
+		input int
+		want int
+	}
+
+	tests := []test{
+		{input: 0, want: 0},
+		{input: 1, want: 1},
+		{input: 2, want: 1},
+		{input: 3, want: 2},
+		{input: 8, want: 21},
+		{input: 38, want: 88169},
+	}
+
+	for _, tc := range tests {
+		got, err := Fibonacci(tc.input)
+		if !reflect.DeepEqual(tc.want, got) {
+			t.Fatalf("input: %v, expected: %v, got: %v, err: %v", tc.input, tc.want, got, err)
+		}
+	}
+}