Macro tree_assertion

macro_rules! tree_assertion {
    (@build $tree_assertion:expr,) => { ... };
    (@build $tree_assertion:expr, var $key:ident: { $($sub:tt)* }) => { ... };
    (@build $tree_assertion:expr, var $key:ident: { $($sub:tt)* }, $($rest:tt)*) => { ... };
    (@build $tree_assertion:expr, var $key:ident: contains { $($sub:tt)* }) => { ... };
    (@build $tree_assertion:expr, var $key:ident: contains { $($sub:tt)* }, $($rest:tt)*) => { ... };
    (@build $tree_assertion:expr, var $key:ident: $assertion:expr) => { ... };
    (@build $tree_assertion:expr, var $key:ident: $assertion:expr, $($rest:tt)*) => { ... };
    (@build $tree_assertion:expr, $key:ident: $($rest:tt)+) => { ... };
    (@build $tree_assertion:expr, ref $key:path: $($rest:tt)+) => { ... };
    (@build $tree_assertion:expr, $key:tt: $($rest:tt)+) => { ... };
    (@build $tree_assertion:expr, $key:expr => $($rest:tt)+) => { ... };
    (@build $tree_assertion:expr, $child_assertion:expr, $($rest:tt)*) => { ... };
    (var $key:ident: { $($sub:tt)* }) => { ... };
    (var $key:ident: contains { $($sub:tt)* }) => { ... };
    ($key:ident: $($rest:tt)+) => { ... };
    ($key:tt: $($rest:tt)+) => { ... };
}

Macro to simplify creating TreeAssertions. Commonly used indirectly through the second parameter of assert_data_tree!. See assert_data_tree! for more usage examples.

Each leaf value must be a type that implements either PropertyAssertion or TreeAssertion.

Example:

// Manual creation of `TreeAssertion`.
let mut root = TreeAssertion::new("root", true);
root.add_property_assertion("a-string-property", Box::new("expected-string-value"));
let mut child = TreeAssertion::new("child", true);
child.add_property_assertion("any-property", Box::new(AnyProperty));
root.add_child_assertion(child);
root.add_child_assertion(opaque_child);

// Creation with `tree_assertion!`.
let root = tree_assertion!(
    root: {
        "a-string-property": "expected-string-value",
        child: {
            "any-property": AnyProperty,
        },
        opaque_child, // required trailing comma for `TreeAssertion` expressions
    }
);

Note that TreeAssertions given directly to the macro must always be followed by ,.