• Macro to simplify tree matching in tests. The first argument is the actual tree passed as a DiagnosticsHierarchyGetter (e.g. a DiagnosticsHierarchy or an Inspector). The second argument is given to tree_assertion! which creates a TreeAssertion to validate the tree.
  • Macro to check a hierarchy with a nice JSON diff. The syntax of the expected value is the same as that of hierarchy!, and essentially the same as assert_data_tree!, except that partial tree matching is not supported (i.e. the keyword contains).
  • Macro to simplify creating TreeAssertions. Commonly used indirectly through the second parameter of assert_data_tree!. See assert_data_tree! for more usage examples.



  • A type which can function as a “view” into a diagnostics hierarchy, optionally allocating a new instance to service a request.
  • Trait implemented by types that can act as properies for assertion.