Function test_QueryGraphExtractSubGraph

tests/unit/test_query_graph.c:355–448

}

void test_QueryGraphExtractSubGraph() {
	//--------------------------------------------------------------------------
	// construct graph
	//--------------------------------------------------------------------------

	// (A)->(B)->(C)->(D)
	const char *relation = "R";

	QGNode *A = QGNode_New("A");
	QGNode *B = QGNode_New("B");
	QGNode *C = QGNode_New("C");
	QGNode *D = QGNode_New("D");

	QGEdge *AB = QGEdge_New(relation, "AB");
	QGEdge *BC = QGEdge_New(relation, "BC");
	QGEdge *CD = QGEdge_New(relation, "CD");

	uint node_cap = 4;
	uint edge_cap = 3;
	QueryGraph *qg = QueryGraph_New(node_cap, edge_cap);
	QueryGraph_AddNode(qg, A);
	QueryGraph_AddNode(qg, B);
	QueryGraph_AddNode(qg, C);
	QueryGraph_AddNode(qg, D);

	QueryGraph_ConnectNodes(qg, A, B, AB);
	QueryGraph_ConnectNodes(qg, B, C, BC);
	QueryGraph_ConnectNodes(qg, C, A, CD);

	//--------------------------------------------------------------------------
	// extract portions of the original query graph
	//--------------------------------------------------------------------------

	const char *query =
		"MATCH (A)-[AB]->(B), (B)-[BC]->(C) MATCH (C)-[CD]->(D) MATCH (D)-[DE]->(E) RETURN D";
	cypher_parse_result_t *parse_result = cypher_parse(query, NULL, NULL, CYPHER_PARSE_ONLY_STATEMENTS);
	AST *ast = AST_Build(parse_result);
	ast->referenced_entities = raxNew();

	const cypher_astnode_t **match_clauses = AST_GetClauses(ast, CYPHER_AST_MATCH);
	const cypher_astnode_t *patterns[3];

	// extract patterns, one per MATCH clause
	patterns[0] = cypher_ast_match_get_pattern(match_clauses[0]);
	patterns[1] = cypher_ast_match_get_pattern(match_clauses[1]);
	patterns[2] = cypher_ast_match_get_pattern(match_clauses[2]);

	// empty sub graph, as the number of patterns specified is 0
	QueryGraph *sub = QueryGraph_ExtractPatterns(qg, patterns, 0);

	// validation, expecting an empty query graph
	TEST_ASSERT(QueryGraph_NodeCount(sub) == 0);
	TEST_ASSERT(QueryGraph_EdgeCount(sub) == 0);
	QueryGraph_Free(sub);

	// single pattern, 2 paths, sub graph: a->b->c
	sub = QueryGraph_ExtractPatterns(qg, patterns, 1);
	TEST_ASSERT(QueryGraph_NodeCount(sub) == 3);