libxl/gentest.py: test JSON parser

The test is done in following steps:

1. initialise libxl_FOO struct
2. generate JSON string A for libxl_FOO struct FOO1
3. convert JSON string A to libxl_FOO struct FOO2
4. generate JSON string B for libxl_FOO struct FOO2
5. compare A and B

If A and B are identical then we are good.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

tools/libxl/gentest.py

@@ -225,10 +225,11 @@ int main(int argc, char **argv)
 """)
 
     for ty in types:
-        f.write("    %s %s_val;\n" % (ty.typename, ty.typename))
+        f.write("    %s %s_val, %s_val_new;\n" % \
+                (ty.typename, ty.typename, ty.typename))
     f.write("""
     int rc;
-    char *s;
+    char *s, *new_s;
     xentoollog_logger_stdiostream *logger;
     libxl_ctx *ctx;
 
@@ -240,20 +241,36 @@ int main(int argc, char **argv)
         exit(1);
     }
 """)
-    f.write("    printf(\"Testing TYPE_to_json()\\n\");\n")
+    f.write("    printf(\"Testing TYPE_to/from_json()\\n\");\n")
     f.write("    printf(\"----------------------\\n\");\n")
     f.write("    printf(\"\\n\");\n")
     for ty in [t for t in types if t.json_gen_fn is not None]:
         arg = ty.typename + "_val"
         f.write("    %s_rand_init(%s);\n" % (ty.typename, \
             ty.pass_arg(arg, isref=False, passby=idl.PASS_BY_REFERENCE)))
+        if not isinstance(ty, idl.Enumeration):
+            f.write("    %s_init(%s_new);\n" % (ty.typename, \
+                ty.pass_arg(arg, isref=False, passby=idl.PASS_BY_REFERENCE)))
         f.write("    s = %s_to_json(ctx, %s);\n" % \
                 (ty.typename, ty.pass_arg(arg, isref=False)))
         f.write("    printf(\"%%s: %%s\\n\", \"%s\", s);\n" % ty.typename)
         f.write("    if (s == NULL) abort();\n")
+        f.write("    rc = %s_from_json(ctx, &%s_val_new, s);\n" % \
+                (ty.typename, ty.typename))
+        f.write("    if (rc) abort();\n")
+        f.write("    new_s = %s_to_json(ctx, %s_new);\n" % \
+                (ty.typename, ty.pass_arg(arg, isref=False)))
+        f.write("    if (new_s == NULL) abort();\n")
+        f.write("    if (strcmp(s, new_s)) {\n")
+        f.write("        printf(\"Huh? Regenerated string different from original string.\\n\");\n")
+        f.write("        printf(\"Regenerated string: %s\\n\", new_s);\n")
+        f.write("        abort();\n")
+        f.write("    }\n")
         f.write("    free(s);\n")
+        f.write("    free(new_s);\n")
         if ty.dispose_fn is not None:
             f.write("    %s(&%s_val);\n" % (ty.dispose_fn, ty.typename))
+            f.write("    %s(&%s_val_new);\n" % (ty.dispose_fn, ty.typename))
         f.write("\n")
 
     f.write("    printf(\"Testing Enumerations\\n\");\n")