src/matchers/property_matcher.rs - platform/external/rust/crates/googletest - Git at Google

 // Copyright 2023 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // There are no visible documentation elements in this module; the declarative
 // macro is documented in the matcher module.
 #![doc(hidden)]

 /// Matches an object which, upon calling the given method on it with the given
 /// arguments, produces a value matched by the given inner matcher.
 ///
 /// This is particularly useful as a nested matcher when the desired
 /// property cannot be accessed through a field and must instead be
 /// extracted through a method call. For example:
 ///
 /// ```
 /// # use googletest::prelude::*;
 /// #[derive(Debug)]
 /// pub struct MyStruct {
 ///     a_field: u32,
 /// }
 ///
 /// impl MyStruct {
 ///     pub fn get_a_field(&self) -> u32 { self.a_field }
 /// }
 ///
 /// let value = vec![MyStruct { a_field: 100 }];
 /// verify_that!(value, contains(property!(MyStruct.get_a_field(), eq(100))))
 /// #    .unwrap();
 /// ```
 ///
 /// **Important**: The method should be pure function with a deterministic
 /// output and no side effects. In particular, in the event of an assertion
 /// failure, it will be invoked a second time, with the assertion failure output
 /// reflecting the *second* invocation.
 ///
 /// If the method returns a *reference*, then it must be preceded by a `*`:
 ///
 /// ```
 /// # use googletest::prelude::*;
 /// # #[derive(Debug)]
 /// # pub struct MyStruct {
 /// #     a_field: u32,
 /// # }
 /// impl MyStruct {
 ///     pub fn get_a_field(&self) -> &u32 { &self.a_field }
 /// }
 ///
 /// # let value = vec![MyStruct { a_field: 100 }];
 /// verify_that!(value, contains(property!(*MyStruct.get_a_field(), eq(100))))
 /// #    .unwrap();
 /// ```
 ///
 /// The method may also take additional arguments:
 ///
 /// ```
 /// # use googletest::prelude::*;
 /// # #[derive(Debug)]
 /// # pub struct MyStruct {
 /// #     a_field: u32,
 /// # }
 /// impl MyStruct {
 ///     pub fn add_to_a_field(&self, a: u32) -> u32 { self.a_field + a }
 /// }
 ///
 /// # let value = vec![MyStruct { a_field: 100 }];
 /// verify_that!(value, contains(property!(MyStruct.add_to_a_field(50), eq(150))))
 /// #    .unwrap();
 /// ```
 ///
 /// Unfortunately, this matcher does *not* work with methods returning string
 /// slices:
 ///
 /// ```compile_fail
 /// # use googletest::prelude::*;
 /// #[derive(Debug)]
 /// pub struct MyStruct {
 ///     a_string: String,
 /// }
 /// impl MyStruct {
 ///     pub fn get_a_string(&self) -> &str { &self.a_string }
 /// }
 ///
 /// let value = MyStruct { a_string: "A string".into() };
 /// verify_that!(value, property!(*MyStruct.get_a_string(), eq("A string"))) // Does not compile
 /// #    .unwrap();
 /// ```
 ///
 /// This macro is analogous to [`field`][crate::matchers::field], except that it
 /// extracts the datum to be matched from the given object by invoking a method
 /// rather than accessing a field.
 ///
 /// The list of arguments may optionally have a trailing comma.
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __property {
     ($($t:tt)*) => { $crate::property_internal!($($t)*) }
 }

 // Internal-only macro created so that the macro definition does not appear in
 // generated documentation.
 #[doc(hidden)]
 #[macro_export]
 macro_rules! property_internal {
     ($($t:ident)::+.$method:tt($($argument:tt),* $(,)?), $m:expr) => {{
          use $crate::matchers::__internal_unstable_do_not_depend_on_these::property_matcher;
         property_matcher(
             |o: &$($t)::+| o.$method($($argument),*),
             &stringify!($method($($argument),*)),
             $m)
     }};

     (* $($t:ident)::+.$method:tt($($argument:tt),* $(,)?), $m:expr) => {{
         use $crate::matchers::__internal_unstable_do_not_depend_on_these::property_ref_matcher;
         property_ref_matcher(
             |o: &$($t)::+| o.$method($($argument),*),
             &stringify!($method($($argument),*)),
             $m)
     }};
 }

 /// Items for use only by the declarative macros in this module.
 ///
 /// **For internal use only. API stablility is not guaranteed!**
 #[doc(hidden)]
 pub mod internal {
     use crate::{
         description::Description,
         matcher::{Matcher, MatcherResult},
     };
     use std::{fmt::Debug, marker::PhantomData};

     /// **For internal use only. API stablility is not guaranteed!**
     #[doc(hidden)]
     pub fn property_matcher<OuterT: Debug, InnerT: Debug, MatcherT: Matcher<ActualT = InnerT>>(
         extractor: impl Fn(&OuterT) -> InnerT,
         property_desc: &'static str,
         inner: MatcherT,
     ) -> impl Matcher<ActualT = OuterT> {
         PropertyMatcher { extractor, property_desc, inner, phantom: Default::default() }
     }

     struct PropertyMatcher<OuterT, ExtractorT, MatcherT> {
         extractor: ExtractorT,
         property_desc: &'static str,
         inner: MatcherT,
         phantom: PhantomData<OuterT>,
     }

     impl<InnerT, OuterT, ExtractorT, MatcherT> Matcher for PropertyMatcher<OuterT, ExtractorT, MatcherT>
     where
         InnerT: Debug,
         OuterT: Debug,
         ExtractorT: Fn(&OuterT) -> InnerT,
         MatcherT: Matcher<ActualT = InnerT>,
     {
         type ActualT = OuterT;

         fn matches(&self, actual: &OuterT) -> MatcherResult {
             self.inner.matches(&(self.extractor)(actual))
         }

         fn describe(&self, matcher_result: MatcherResult) -> Description {
             format!(
                 "has property `{}`, which {}",
                 self.property_desc,
                 self.inner.describe(matcher_result)
             )
             .into()
         }

         fn explain_match(&self, actual: &OuterT) -> Description {
             let actual_inner = (self.extractor)(actual);
             format!(
                 "whose property `{}` is `{:#?}`, {}",
                 self.property_desc,
                 actual_inner,
                 self.inner.explain_match(&actual_inner)
             )
             .into()
         }
     }

     /// **For internal use only. API stablility is not guaranteed!**
     #[doc(hidden)]
     pub fn property_ref_matcher<OuterT, InnerT, MatcherT>(
         extractor: fn(&OuterT) -> &InnerT,
         property_desc: &'static str,
         inner: MatcherT,
     ) -> impl Matcher<ActualT = OuterT>
     where
         OuterT: Debug,
         InnerT: Debug + ?Sized,
         MatcherT: Matcher<ActualT = InnerT>,
     {
         PropertyRefMatcher { extractor, property_desc, inner }
     }

     struct PropertyRefMatcher<InnerT: ?Sized, OuterT, MatcherT> {
         extractor: fn(&OuterT) -> &InnerT,
         property_desc: &'static str,
         inner: MatcherT,
     }

     impl<InnerT: Debug + ?Sized, OuterT: Debug, MatcherT: Matcher<ActualT = InnerT>> Matcher
         for PropertyRefMatcher<InnerT, OuterT, MatcherT>
     {
         type ActualT = OuterT;

         fn matches(&self, actual: &OuterT) -> MatcherResult {
             self.inner.matches((self.extractor)(actual))
         }

         fn describe(&self, matcher_result: MatcherResult) -> Description {
             format!(
                 "has property `{}`, which {}",
                 self.property_desc,
                 self.inner.describe(matcher_result)
             )
             .into()
         }

         fn explain_match(&self, actual: &OuterT) -> Description {
             let actual_inner = (self.extractor)(actual);
             format!(
                 "whose property `{}` is `{:#?}`, {}",
                 self.property_desc,
                 actual_inner,
                 self.inner.explain_match(actual_inner)
             )
             .into()
         }
     }
 }
	// Copyright 2023 Google LLC
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// There are no visible documentation elements in this module; the declarative
	// macro is documented in the matcher module.
	#![doc(hidden)]

	/// Matches an object which, upon calling the given method on it with the given
	/// arguments, produces a value matched by the given inner matcher.
	///
	/// This is particularly useful as a nested matcher when the desired
	/// property cannot be accessed through a field and must instead be
	/// extracted through a method call. For example:
	///
	/// ```
	/// # use googletest::prelude::*;
	/// #[derive(Debug)]
	/// pub struct MyStruct {
	/// a_field: u32,
	/// }
	///
	/// impl MyStruct {
	/// pub fn get_a_field(&self) -> u32 { self.a_field }
	/// }
	///
	/// let value = vec![MyStruct { a_field: 100 }];
	/// verify_that!(value, contains(property!(MyStruct.get_a_field(), eq(100))))
	/// # .unwrap();
	/// ```
	///
	/// Important: The method should be pure function with a deterministic
	/// output and no side effects. In particular, in the event of an assertion
	/// failure, it will be invoked a second time, with the assertion failure output
	/// reflecting the second invocation.
	///
	/// If the method returns a reference, then it must be preceded by a `*`:
	///
	/// ```
	/// # use googletest::prelude::*;
	/// # #[derive(Debug)]
	/// # pub struct MyStruct {
	/// # a_field: u32,
	/// # }
	/// impl MyStruct {
	/// pub fn get_a_field(&self) -> &u32 { &self.a_field }
	/// }
	///
	/// # let value = vec![MyStruct { a_field: 100 }];
	/// verify_that!(value, contains(property!(*MyStruct.get_a_field(), eq(100))))
	/// # .unwrap();
	/// ```
	///
	/// The method may also take additional arguments:
	///
	/// ```
	/// # use googletest::prelude::*;
	/// # #[derive(Debug)]
	/// # pub struct MyStruct {
	/// # a_field: u32,
	/// # }
	/// impl MyStruct {
	/// pub fn add_to_a_field(&self, a: u32) -> u32 { self.a_field + a }
	/// }
	///
	/// # let value = vec![MyStruct { a_field: 100 }];
	/// verify_that!(value, contains(property!(MyStruct.add_to_a_field(50), eq(150))))
	/// # .unwrap();
	/// ```
	///
	/// Unfortunately, this matcher does not work with methods returning string
	/// slices:
	///
	/// ```compile_fail
	/// # use googletest::prelude::*;
	/// #[derive(Debug)]
	/// pub struct MyStruct {
	/// a_string: String,
	/// }
	/// impl MyStruct {
	/// pub fn get_a_string(&self) -> &str { &self.a_string }
	/// }
	///
	/// let value = MyStruct { a_string: "A string".into() };
	/// verify_that!(value, property!(*MyStruct.get_a_string(), eq("A string"))) // Does not compile
	/// # .unwrap();
	/// ```
	///
	/// This macro is analogous to [`field`][crate::matchers::field], except that it
	/// extracts the datum to be matched from the given object by invoking a method
	/// rather than accessing a field.
	///
	/// The list of arguments may optionally have a trailing comma.
	#[macro_export]
	#[doc(hidden)]
	macro_rules! __property {
	($($t:tt)) => { $crate::property_internal!($($t)) }
	}

	// Internal-only macro created so that the macro definition does not appear in
	// generated documentation.
	#[doc(hidden)]
	#[macro_export]
	macro_rules! property_internal {
	($($t:ident)::+.$method:tt($($argument:tt),* $(,)?), $m:expr) => {{
	use $crate::matchers::__internal_unstable_do_not_depend_on_these::property_matcher;
	property_matcher(
	\|o: &$($t)::+\| o.$method($($argument),*),
	&stringify!($method($($argument),*)),
	$m)
	}};

	(* $($t:ident)::+.$method:tt($($argument:tt),* $(,)?), $m:expr) => {{
	use $crate::matchers::__internal_unstable_do_not_depend_on_these::property_ref_matcher;
	property_ref_matcher(
	\|o: &$($t)::+\| o.$method($($argument),*),
	&stringify!($method($($argument),*)),
	$m)
	}};
	}

	/// Items for use only by the declarative macros in this module.
	///
	/// For internal use only. API stablility is not guaranteed!
	#[doc(hidden)]
	pub mod internal {
	use crate::{
	description::Description,
	matcher::{Matcher, MatcherResult},
	};
	use std::{fmt::Debug, marker::PhantomData};

	/// For internal use only. API stablility is not guaranteed!
	#[doc(hidden)]
	pub fn property_matcher<OuterT: Debug, InnerT: Debug, MatcherT: Matcher<ActualT = InnerT>>(
	extractor: impl Fn(&OuterT) -> InnerT,
	property_desc: &'static str,
	inner: MatcherT,
	) -> impl Matcher<ActualT = OuterT> {
	PropertyMatcher { extractor, property_desc, inner, phantom: Default::default() }
	}

	struct PropertyMatcher<OuterT, ExtractorT, MatcherT> {
	extractor: ExtractorT,
	property_desc: &'static str,
	inner: MatcherT,
	phantom: PhantomData<OuterT>,
	}

	impl<InnerT, OuterT, ExtractorT, MatcherT> Matcher for PropertyMatcher<OuterT, ExtractorT, MatcherT>
	where
	InnerT: Debug,
	OuterT: Debug,
	ExtractorT: Fn(&OuterT) -> InnerT,
	MatcherT: Matcher<ActualT = InnerT>,
	{
	type ActualT = OuterT;

	fn matches(&self, actual: &OuterT) -> MatcherResult {
	self.inner.matches(&(self.extractor)(actual))
	}

	fn describe(&self, matcher_result: MatcherResult) -> Description {
	format!(
	"has property `{}`, which {}",
	self.property_desc,
	self.inner.describe(matcher_result)
	)
	.into()
	}

	fn explain_match(&self, actual: &OuterT) -> Description {
	let actual_inner = (self.extractor)(actual);
	format!(
	"whose property `{}` is `{:#?}`, {}",
	self.property_desc,
	actual_inner,
	self.inner.explain_match(&actual_inner)
	)
	.into()
	}
	}

	/// For internal use only. API stablility is not guaranteed!
	#[doc(hidden)]
	pub fn property_ref_matcher<OuterT, InnerT, MatcherT>(
	extractor: fn(&OuterT) -> &InnerT,
	property_desc: &'static str,
	inner: MatcherT,
	) -> impl Matcher<ActualT = OuterT>
	where
	OuterT: Debug,
	InnerT: Debug + ?Sized,
	MatcherT: Matcher<ActualT = InnerT>,
	{
	PropertyRefMatcher { extractor, property_desc, inner }
	}

	struct PropertyRefMatcher<InnerT: ?Sized, OuterT, MatcherT> {
	extractor: fn(&OuterT) -> &InnerT,
	property_desc: &'static str,
	inner: MatcherT,
	}

	impl<InnerT: Debug + ?Sized, OuterT: Debug, MatcherT: Matcher<ActualT = InnerT>> Matcher
	for PropertyRefMatcher<InnerT, OuterT, MatcherT>
	{
	type ActualT = OuterT;

	fn matches(&self, actual: &OuterT) -> MatcherResult {
	self.inner.matches((self.extractor)(actual))
	}

	fn describe(&self, matcher_result: MatcherResult) -> Description {
	format!(
	"has property `{}`, which {}",
	self.property_desc,
	self.inner.describe(matcher_result)
	)
	.into()
	}

	fn explain_match(&self, actual: &OuterT) -> Description {
	let actual_inner = (self.extractor)(actual);
	format!(
	"whose property `{}` is `{:#?}`, {}",
	self.property_desc,
	actual_inner,
	self.inner.explain_match(actual_inner)
	)
	.into()
	}
	}
	}