[core] Add a test.py file that contains sanity methods used for validation

For now, it contains methods allowing to check whether a template provided
as an argument is valid (i.e. has no compatibility issue).

It performs a check that's very similar to what `test_templatesVersions`
was doing, but it allows this check to be performed from outside of
Meshroom.

meshroom/core/test.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python
+# coding:utf-8
+
+from meshroom.core import pipelineTemplates, Version
+from meshroom.core.node import CompatibilityIssue, CompatibilityNode
+from meshroom.core.graphIO import GraphIO
+
+import meshroom
+
+import json
+
+def checkTemplateVersions(path: str) -> bool:
+    """ Check whether there is a compatibility issue with the nodes saved in the template provided with "path". """
+    meshroom.core.initNodes()
+
+    with open(path) as jsonFile:
+        fileData = json.load(jsonFile)
+
+    graphData = fileData.get(GraphIO.Keys.Graph, fileData)
+    if not isinstance(graphData, dict):
+        return False
+
+    header = fileData.get(GraphIO.Keys.Header, {})
+    if not header.get("template", False):
+        return False
+    nodesVersions = header.get(GraphIO.Keys.NodesVersions, {})
+
+    for _, nodeData in graphData.items():
+        nodeType = nodeData["nodeType"]
+        if not nodeType in meshroom.core.nodesDesc:
+            return False
+
+        nodeDesc = meshroom.core.nodesDesc[nodeType]
+        currentNodeVersion = meshroom.core.nodeVersion(nodeDesc)
+
+        inputs = nodeData.get("inputs", {})
+        internalInputs = nodeData.get("internalInputs", {})
+        version = nodesVersions.get(nodeType, None)
+
+        compatibilityIssue = None
+
+        if version and currentNodeVersion and Version(version).major != Version(currentNodeVersion).major:
+            compatibilityIssue = CompatibilityIssue.VersionConflict
+        else:
+            for attrName, value in inputs.items():
+                if not CompatibilityNode.attributeDescFromName(nodeDesc.inputs, attrName, value):
+                    compatibilityIssue = CompatibilityIssue.DescriptionConflict
+                    break
+            for attrName, value in internalInputs.items():
+                if not CompatibilityNode.attributeDescFromName(nodeDesc.internalInputs, attrName, value):
+                    compatibilityIssue = CompatibilityIssue.DescriptionConflict
+                    break
+
+        if compatibilityIssue is not None:
+            print("{} in {} for node {}".format(compatibilityIssue, path, nodeType))
+            return False
+
+    return True
+
+
+def checkAllTemplatesVersions() -> bool:
+    meshroom.core.initPipelines()
+
+    validVersions = []
+    for _, path in pipelineTemplates.items():
+        validVersions.append(checkTemplateVersions(path))
+
+    return all(validVersions)