initial

main_test.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"strconv"
+	"testing"
+)
+
+func TestGenerateCPFLength(t *testing.T) {
+	cpf := generateCPF()
+	if len(cpf) != 11 {
+		t.Fatalf("expected length 11, got %d: %s", len(cpf), cpf)
+	}
+}
+
+func TestGenerateCPFCheckDigits(t *testing.T) {
+	for range 100 {
+		cpf := generateCPF()
+		if !isValidCPF(cpf) {
+			t.Fatalf("invalid CPF generated: %s", cpf)
+		}
+	}
+}
+
+func TestGenerateCPFAllDigits(t *testing.T) {
+	seen := make(map[string]bool)
+	for range 1000 {
+		cpf := generateCPF()
+		if seen[cpf] {
+			t.Fatal("duplicate CPF generated")
+		}
+		seen[cpf] = true
+	}
+}
+
+func isValidCPF(cpf string) bool {
+	if len(cpf) != 11 {
+		return false
+	}
+
+	digits := make([]int, 11)
+	for i, ch := range cpf {
+		d, err := strconv.Atoi(string(ch))
+		if err != nil {
+			return false
+		}
+		digits[i] = d
+	}
+
+	allEqual := true
+	for i := 1; i < 11; i++ {
+		if digits[i] != digits[0] {
+			allEqual = false
+			break
+		}
+	}
+	if allEqual {
+		return false
+	}
+
+	sum := 0
+	for i := range 9 {
+		sum += digits[i] * (10 - i)
+	}
+	rem := sum % 11
+	var d1 int
+	if rem < 2 {
+		d1 = 0
+	} else {
+		d1 = 11 - rem
+	}
+	if d1 != digits[9] {
+		return false
+	}
+
+	sum = 0
+	for i := range 10 {
+		sum += digits[i] * (11 - i)
+	}
+	rem = sum % 11
+	var d2 int
+	if rem < 2 {
+		d2 = 0
+	} else {
+		d2 = 11 - rem
+	}
+	return d2 == digits[10]
+}