Initial commit.

collections/sum.go

@@ -0,0 +1,19 @@
+package collections
+
+func Sum(numbers []int) int {
+	sum := 0
+	for _, number := range numbers {
+		sum += number
+	}
+
+	return sum
+}
+
+func SumAll(numberSlices ...[]int) []int {
+	var sums []int
+	for _, numbers := range numberSlices {
+		sums = append(sums, Sum(numbers))
+	}
+
+	return sums
+}

collections/sum_test.go

@@ -0,0 +1,26 @@
+package collections
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestSum(t *testing.T) {
+	numbers := []int{1, 2, 3, 4, 5}
+
+	got := Sum(numbers)
+	want := 15
+
+	if got != want {
+		t.Errorf("got %d want %d given %v", got, want, numbers)
+	}
+}
+
+func TestSumAll(t *testing.T) {
+	got := SumAll([]int{1, 2}, []int{1, 2, 3, 4, 5})
+	want := []int{3, 15}
+
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("got %d want %d", got, want)
+	}
+}

go.mod

@@ -0,0 +1,3 @@
+module learn-go-with-tests
+
+go 1.22.7

hello-world/hello.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+const spanish = "Spanish"
+const spanishHelloPrefix = "Hola, "
+const englishHelloPrefix = "Hello, "
+
+func Hello(name, language string) string {
+	if name == "" {
+		name = "world"
+	}
+
+	prefix := englishHelloPrefix
+	switch language {
+	case spanish:
+		prefix = spanishHelloPrefix
+	}
+
+	return prefix + name
+}
+
+func main() {
+	fmt.Println(Hello("World", ""))
+}

hello-world/hello_test.go

@@ -0,0 +1,32 @@
+package main
+
+import "testing"
+
+func TestHello(t *testing.T) {
+	t.Run("say hello to given name", func(t *testing.T) {
+		got := Hello("Judas", "")
+		want := "Hello, Judas"
+
+		assertCorrectMessage(t, got, want)
+	})
+	t.Run("hello world on empty string", func(t *testing.T) {
+		got := Hello("", "")
+		want := "Hello, world"
+
+		assertCorrectMessage(t, got, want)
+	})
+	t.Run("spanish", func(t *testing.T) {
+		got := Hello("Marjorie", "Spanish")
+		want := "Hola, Marjorie"
+
+		assertCorrectMessage(t, got, want)
+	})
+}
+
+func assertCorrectMessage(t testing.TB, got, want string) {
+	t.Helper()
+
+	if got != want {
+		t.Errorf("got %q want %q", got, want)
+	}
+}

integers/adder.go

@@ -0,0 +1,6 @@
+package integers
+
+// Returns the sum of two integers.
+func Add(x, y int) int {
+	return x + y
+}

integers/adder_test.go

@@ -0,0 +1,21 @@
+package integers
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestAdder(t *testing.T) {
+	sum := Add(2, 2)
+	expected := 4
+
+	if sum != expected {
+		t.Errorf("expected %d got %d", expected, sum)
+	}
+}
+
+func ExampleAdd() {
+	sum := Add(1, 5)
+	fmt.Println(sum)
+	// Output: 6
+}

iteration/repeat_test.go

@@ -0,0 +1,27 @@
+package iteration
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestRepeat(t *testing.T) {
+	repeated := Repeat("a", 3)
+	expected := "aaa"
+
+	if repeated != expected {
+		t.Errorf("expected %q got %q", expected, repeated)
+	}
+}
+
+func BenchmarkRepeat(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		Repeat("a", 5)
+	}
+}
+
+func ExampleRepeat() {
+	res := Repeat("a", 5)
+	fmt.Println(res)
+	// Output: aaaaa
+}

iteration/repeater.go

@@ -0,0 +1,10 @@
+package iteration
+
+func Repeat(char string, n int) string {
+	var repeated string
+	for i := 0; i < n; i++ {
+		repeated += char
+	}
+
+	return repeated
+}

pointererror/pointererror.go

@@ -0,0 +1,22 @@
+package pointererror
+
+import "fmt"
+
+type Bitcoin int
+
+func (b Bitcoin) String() string {
+	return fmt.Sprintf("%d BTC", b)
+}
+
+type Wallet struct {
+	balance Bitcoin
+}
+
+func (w *Wallet) Deposit(amount Bitcoin) {
+	w.balance += amount * 2
+}
+
+func (w *Wallet) Balance() Bitcoin {
+	fmt.Printf("address of balance in Balance is %p \n", &w.balance)
+	return w.balance
+}

pointererror/pointererror_test.go

@@ -0,0 +1,22 @@
+package pointererror
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestWallet(t *testing.T) {
+	wallet := Wallet{}
+
+	wallet.Deposit(Bitcoin(10))
+
+	got := wallet.Balance()
+
+	fmt.Printf("address of balance in test is %p \n", &wallet.balance)
+
+	want := Bitcoin(10)
+
+	if got != want {
+		t.Errorf("got %s want %s", got, want)
+	}
+}

shapes/shapes.go

@@ -0,0 +1,10 @@
+package shapes
+
+type Rectangle struct {
+	Width  float64
+	Height float64
+}
+
+func Perimeter(rec Rectangle) float64 {
+	return 2 * (rec.Width + rec.Height)
+}

shapes/shapes_test.go

@@ -0,0 +1,14 @@
+package shapes
+
+import "testing"
+
+func TestPerimeter(t *testing.T) {
+	rectangle := Rectangle{10.00, 10.00}
+
+	got := Perimeter(rectangle)
+	want := 40.0
+
+	if got != want {
+		t.Errorf("got %.2f want %.2f", got, want)
+	}
+}