tests: Add testing of backing store string parser

As we already test that the extraction of the backing store string works
well additional tests for the backing store string parser can be made
simpler.

Export virStorageSourceNewFromBackingAbsolute and use it to parse the
backing store strings, format them using virDomainDiskSourceFormat and
match them against expected XMLs.

src/libvirt_private.syms

@@ -2364,6 +2364,7 @@ virStorageSourceIsBlockLocal;
 virStorageSourceIsEmpty;
 virStorageSourceIsLocalStorage;
 virStorageSourceNewFromBacking;
+virStorageSourceNewFromBackingAbsolute;
 virStorageSourceParseRBDColonString;
 virStorageSourcePoolDefFree;
 virStorageSourcePoolModeTypeFromString;

src/util/virstoragefile.c

@@ -2514,7 +2514,7 @@ virStorageSourceParseBackingColon(virStorageSourcePtr src,
 }
 
 
-static virStorageSourcePtr
+virStorageSourcePtr
 virStorageSourceNewFromBackingAbsolute(const char *path)
 {
     virStorageSourcePtr ret;

src/util/virstoragefile.h

@@ -380,4 +380,7 @@ int virStorageFileGetRelativeBackingPath(virStorageSourcePtr from,
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
 
 int virStorageFileCheckCompat(const char *compat);
+
+virStorageSourcePtr virStorageSourceNewFromBackingAbsolute(const char *path);
+
 #endif /* __VIR_STORAGE_FILE_H__ */

tests/virstoragetest.c

@@ -665,6 +665,58 @@ testPathRelative(const void *args)
 }
 
 
+struct testBackingParseData {
+    const char *backing;
+    const char *expect;
+};
+
+static int
+testBackingParse(const void *args)
+{
+    const struct testBackingParseData *data = args;
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    virStorageSourcePtr src = NULL;
+    char *xml = NULL;
+    int ret = -1;
+
+    if (!(src = virStorageSourceNewFromBackingAbsolute(data->backing))) {
+        if (!data->expect)
+            ret = 0;
+
+        goto cleanup;
+    }
+
+    if (src && !data->expect) {
+        fprintf(stderr, "parsing of backing store string '%s' should "
+                        "have failed\n", data->backing);
+        goto cleanup;
+    }
+
+    if (virDomainDiskSourceFormat(&buf, src, 0, 0) < 0 ||
+        !(xml = virBufferContentAndReset(&buf))) {
+        fprintf(stderr, "failed to format disk source xml\n");
+        goto cleanup;
+    }
+
+    if (!STREQ(xml, data->expect)) {
+        fprintf(stderr, "\n backing store string '%s'\n"
+                        "expected storage source xml:\n%s\n"
+                        "actual storage source xml:\n%s\n",
+                        data->backing, data->expect, xml);
+        goto cleanup;
+    }
+
+    ret = 0;
+
+ cleanup:
+    virStorageSourceFree(src);
+    virBufferFreeAndReset(&buf);
+    VIR_FREE(xml);
+
+    return ret;
+}
+
+
 static int
 mymain(void)
 {
@@ -674,6 +726,7 @@ mymain(void)
     struct testLookupData data2;
     struct testPathCanonicalizeData data3;
     struct testPathRelativeBacking data4;
+    struct testBackingParseData data5;
     virStorageSourcePtr chain = NULL;
     virStorageSourcePtr chain2; /* short for chain->backingStore */
     virStorageSourcePtr chain3; /* short for chain2->backingStore */
@@ -1276,6 +1329,33 @@ mymain(void)
     TEST_RELATIVE_BACKING(21, backingchain[10], backingchain[11], "../../../../blah/image4");
     TEST_RELATIVE_BACKING(22, backingchain[11], backingchain[11], "../blah/image4");
 
+
+    virTestCounterReset("Backing store parse ");
+
+#define TEST_BACKING_PARSE(bck, xml)                                           \
+    do {                                                                       \
+        data5.backing = bck;                                                   \
+        data5.expect = xml;                                                    \
+        if (virTestRun(virTestCounterNext(),                                   \
+                       testBackingParse, &data5) < 0)                          \
+            ret = -1;                                                          \
+    } while (0)
+
+    TEST_BACKING_PARSE("path", "<source file='path'/>\n");
+    TEST_BACKING_PARSE("://", NULL);
+    TEST_BACKING_PARSE("http://example.com/file",
+                       "<source protocol='http' name='file'>\n"
+                       "  <host name='example.com'/>\n"
+                       "</source>\n");
+    TEST_BACKING_PARSE("rbd:testshare:id=asdf:mon_host=example.com",
+                       "<source protocol='rbd' name='testshare'>\n"
+                       "  <host name='example.com'/>\n"
+                       "</source>\n");
+    TEST_BACKING_PARSE("nbd:example.org:6000:exportname=blah",
+                       "<source protocol='nbd' name='blah'>\n"
+                       "  <host name='example.org' port='6000'/>\n"
+                       "</source>\n");
+
  cleanup:
     /* Final cleanup */
     virStorageSourceFree(chain);