feat: add bigInt function with comprehensive tests

include/faker-cxx/number.h

@@ -4,6 +4,7 @@
 #include <optional>
 #include <random>
 #include <stdexcept>
+#include <optional>
 
 #include "faker-cxx/export.h"
 #include "faker-cxx/types/hex.h"
@@ -272,4 +273,18 @@ FAKER_CXX_EXPORT std::string binary(int length = 1);
  * @endcode
  */
 FAKER_CXX_EXPORT std::string binary(int min, int max);
+
+/**
+ * @brief Generates a random big integer number in the given range, bounds included.
+ *
+ * @param min The minimum value of the range.
+ * @param max The maximum value of the range.
+ *
+ * @return A random big integer number.
+ *
+ * @code
+ * faker::number::bigInt(1000000000, 9999999999) // Example output: 4593830193
+ * @endcode
+ */
+FAKER_CXX_EXPORT std::optional<long long> bigInt(std::optional<long long> min = std::nullopt, std::optional<long long> max = std::nullopt);
 }

src/modules/number.cpp

@@ -115,4 +115,23 @@ std::string binary(int min, int max)
 
     return "0b" + output;
 }
+
+std::optional<long long> bigInt(std::optional<long long> min, std::optional<long long> max)
+{
+    const long long DEFAULT_MAX = 9999999999999999LL;
+    const long long DEFAULT_MIN = 1LL;
+
+    long long actualMin = min.value_or(DEFAULT_MIN);
+    long long actualMax = max.value_or(DEFAULT_MAX);
+
+    if (actualMin > actualMax)
+    {
+        throw std::invalid_argument("min cannot be greater than max");
+    }
+
+    static std::mt19937_64 gen(std::random_device{}());
+    std::uniform_int_distribution<long long> dist(actualMin, actualMax);
+
+    return dist(gen);
+}
 }

tests/modules/number_test.cpp

@@ -254,3 +254,34 @@ TEST_F(NumberTest, givenMinBiggerThanMax_shouldThrowInvalidArgument)
 {
     ASSERT_THROW(binary(10, 1), std::invalid_argument);
 }
+
+TEST_F(NumberTest, givenValidRange_shouldGenerateBigIntWithinRange)
+{
+    const long min = 1000000000000000L;
+    const long max = 9999999999999999L;
+
+    const long actualRandomBigInt = bigInt(min, max).value();
+
+    ASSERT_GE(actualRandomBigInt, min);  
+    ASSERT_LE(actualRandomBigInt, max);  
+}
+
+TEST_F(NumberTest, givenNegativeRange_shouldGenerateBigIntWithinRange)
+{
+    const long min = -1000000000000000L;
+    const long max = -1L;
+
+    const long actualRandomBigInt = bigInt(min, max).value();
+
+    ASSERT_GE(actualRandomBigInt, min); 
+    ASSERT_LE(actualRandomBigInt, max);  
+}
+
+TEST_F(NumberTest, givenSameRange_shouldGenerateExactBigInt)
+{
+    const long minMax = 5000000000000000L;
+
+    const long actualRandomBigInt = bigInt(minMax, minMax).value();
+
+    ASSERT_EQ(actualRandomBigInt, minMax);  
+}