tests: core::strtol: test for some more edge-cases

Some edge cases were currently completely untested, e.g. parsing numbers
greater than INT64_{MIN,MAX}, truncating buffers by length and invalid
characters. Add tests to verify that the system under test performs as
expected.

(cherry picked from commit 39087ab8)

tests/core/strtol.c

@@ -20,13 +20,24 @@ static void assert_l64_parses(const char *string, int64_t expected, int base)
 	cl_assert_equal_i(i, expected);
 }
 
+static void assert_l64_fails(const char *string, int base)
+{
+	int64_t i;
+	cl_git_fail(git__strntol64(&i, string, strlen(string), NULL, base));
+}
+
 void test_core_strtol__int32(void)
 {
 	assert_l32_parses("123", 123, 10);
 	assert_l32_parses("  +123 ", 123, 10);
 	assert_l32_parses("  +2147483647 ", 2147483647, 10);
 	assert_l32_parses("  -2147483648 ", -2147483648LL, 10);
+	assert_l32_parses("A", 10, 16);
+	assert_l32_parses("1x1", 1, 10);
 
+	assert_l32_fails("", 10);
+	assert_l32_fails("a", 10);
+	assert_l32_fails("x10x", 10);
 	assert_l32_fails("  2147483657 ", 10);
 	assert_l32_fails("  -2147483657 ", 10);
 }
@@ -43,4 +54,24 @@ void test_core_strtol__int64(void)
 	assert_l64_parses("   -9223372036854775808  ", INT64_MIN, 10);
 	assert_l64_parses("   0x7fffffffffffffff  ", INT64_MAX, 16);
 	assert_l64_parses("   -0x8000000000000000   ", INT64_MIN, 16);
+	assert_l64_parses("1a", 26, 16);
+	assert_l64_parses("1A", 26, 16);
+
+	assert_l64_fails("", 10);
+	assert_l64_fails("a", 10);
+	assert_l64_fails("x10x", 10);
+	assert_l64_fails("0x8000000000000000", 16);
+	assert_l64_fails("-0x8000000000000001", 16);
+}
+
+void test_core_strtol__buffer_length_truncates(void)
+{
+	int32_t i32;
+	int64_t i64;
+
+	cl_git_pass(git__strntol32(&i32, "11", 1, NULL, 10));
+	cl_assert_equal_i(i32, 1);
+
+	cl_git_pass(git__strntol64(&i64, "11", 1, NULL, 10));
+	cl_assert_equal_i(i64, 1);
 }