Added file read test

tests/file.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+
+int main(int argc, const char **argv)
+{
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s <file>\n", argv[0]);
+        return -1;
+    }
+
+    FILE *fp = fopen(argv[1], "r");
+    if (!fp) {
+        fprintf(stderr, "cannot open %s\n", argv[1]);
+        return -1;
+    }
+
+    char c;
+    while ((c = fgetc(fp)) != EOF) {
+        fputc(c, stdout);
+    }
+
+    fflush(stdout);
+
+    return 0;
+}