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Test Neo4j queries in Cratis Arc

Install Cratis.Arc.Neo4j.Testing in your specification project to answer graph queries with rows you set up:

Terminal window
dotnet add package Cratis.Arc.Neo4j.Testing

UseGraphSessionSubstitute() replaces the session in a service collection, for instance the Services of a command scenario, and returns a GraphSessionSubstitute:

var services = new ServiceCollection();
var graph = services.UseGraphSessionSubstitute();
graph.Returns("MATCH (p:Person)", new GroupMember(personId, new PersonName("Ada")));


var members = await GroupMember.MembersOf(groupId, graph);
  • Returns<T>(fragment, rows) sets up the rows a query answers with when its Cypher contains the fragment, ignoring case. A query nothing was set up for returns no rows.
  • Executions lists the queries that were run, with their parameters as the driver would get them: concepts unwrapped and $namespace included. Assert on it to check a query was filtered or bound correctly.
  • Namespace, DatabaseName, DatabaseMode and AccessMode can be set to exercise code that depends on them.

UseGraphSession(session) replaces the session with one you built, for instance an NSubstitute substitute for IGraphSession. Either replacement also answers IGraphSessionFactory.Open.

Run and Session need a real driver and throw on the substitute, so keep application code that maps rows on Query and QuerySingle, or cover the driver calls with an integration test against Neo4j.

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