Tests: close file handles before asserting

Avoids getting ERROR_SHARING_VIOLATION on win32
and killing the entire clar run.

tests-clar/checkout/checkout.c

@@ -24,13 +24,17 @@ static void test_file_contents(const char *path, const char *expectedcontents)
 {
 	int fd;
 	char buffer[1024] = {0};
+	size_t expectedlen, actuallen;
 
 	fd = p_open(path, O_RDONLY);
 	cl_assert(fd >= 0);
 
-	cl_assert_equal_i(p_read(fd, buffer, 1024), strlen(expectedcontents));
-	cl_assert_equal_s(expectedcontents, buffer);
+	expectedlen = strlen(expectedcontents);
+	actuallen = p_read(fd, buffer, 1024);
 	cl_git_pass(p_close(fd));
+
+	cl_assert_equal_i(actuallen, expectedlen);
+	cl_assert_equal_s(buffer, expectedcontents);
 }