From 26606feed7f373975e2a74d39c68904501b19153 Mon Sep 17 00:00:00 2001
From: Rachel Brindle <you@subluminal.net>
Date: Mon, 3 Apr 2023 23:29:58 -0700
Subject: [PATCH] satisfyAllOf with toEventually should only evaluate the
 expression once each poll

Fixes #529
---
 Sources/Nimble/Expression.swift                   |  9 +++++++++
 Sources/Nimble/Matchers/PostNotification.swift    |  2 +-
 Sources/Nimble/Matchers/SatisfyAllOf.swift        |  5 +++--
 Tests/NimbleTests/Matchers/SatisfyAllOfTest.swift | 12 ++++++++++++
 4 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/Sources/Nimble/Expression.swift b/Sources/Nimble/Expression.swift
index 1ac29b254..bae39e451 100644
--- a/Sources/Nimble/Expression.swift
+++ b/Sources/Nimble/Expression.swift
@@ -94,4 +94,13 @@ public struct Expression<Value> {
             isClosure: isClosure
         )
     }
+
+    public func withCaching() -> Expression<Value> {
+        return Expression(
+            memoizedExpression: memoizedClosure { try self.evaluate() },
+            location: self.location,
+            withoutCaching: false,
+            isClosure: isClosure
+        )
+    }
 }
diff --git a/Sources/Nimble/Matchers/PostNotification.swift b/Sources/Nimble/Matchers/PostNotification.swift
index e04bf556e..750b46a88 100644
--- a/Sources/Nimble/Matchers/PostNotification.swift
+++ b/Sources/Nimble/Matchers/PostNotification.swift
@@ -61,7 +61,7 @@ private func _postNotifications<Out>(
             withoutCaching: true
         )
 
-        assert(pthread_equal(mainThread, pthread_self()) != 0, "Only expecting closure to be evaluated on main thread.")
+        assert(Thread.isMainThread, "Only expecting closure to be evaluated on main thread.")
         if !once {
             once = true
             _ = try actualExpression.evaluate()
diff --git a/Sources/Nimble/Matchers/SatisfyAllOf.swift b/Sources/Nimble/Matchers/SatisfyAllOf.swift
index 50ab64150..2df6a7091 100644
--- a/Sources/Nimble/Matchers/SatisfyAllOf.swift
+++ b/Sources/Nimble/Matchers/SatisfyAllOf.swift
@@ -8,10 +8,11 @@ public func satisfyAllOf<T>(_ predicates: Predicate<T>...) -> Predicate<T> {
 /// provided in the array of matchers.
 public func satisfyAllOf<T>(_ predicates: [Predicate<T>]) -> Predicate<T> {
     return Predicate.define { actualExpression in
+        let cachedExpression = actualExpression.withCaching()
         var postfixMessages = [String]()
         var status: PredicateStatus = .matches
         for predicate in predicates {
-            let result = try predicate.satisfies(actualExpression)
+            let result = try predicate.satisfies(cachedExpression)
             if result.status == .fail {
                 status = .fail
             } else if result.status == .doesNotMatch, status != .fail {
@@ -21,7 +22,7 @@ public func satisfyAllOf<T>(_ predicates: [Predicate<T>]) -> Predicate<T> {
         }
 
         var msg: ExpectationMessage
-        if let actualValue = try actualExpression.evaluate() {
+        if let actualValue = try cachedExpression.evaluate() {
             msg = .expectedCustomValueTo(
                 "match all of: " + postfixMessages.joined(separator: ", and "),
                 actual: "\(actualValue)"
diff --git a/Tests/NimbleTests/Matchers/SatisfyAllOfTest.swift b/Tests/NimbleTests/Matchers/SatisfyAllOfTest.swift
index caae73501..e57626329 100644
--- a/Tests/NimbleTests/Matchers/SatisfyAllOfTest.swift
+++ b/Tests/NimbleTests/Matchers/SatisfyAllOfTest.swift
@@ -48,4 +48,16 @@ final class SatisfyAllOfTest: XCTestCase {
         expect(false).toNot(beTrue() && beFalse())
         expect(true).toNot(beTruthy() && beFalsy())
     }
+
+    func testSatisfyAllOfCachesExpressionBeforePassingToPredicates() {
+        // This is not a great example of assertion writing - functions being asserted on in Expressions should not have side effects.
+        // But we should still handle those cases anyway.
+        var value: Int = 0
+        func testFunction() -> Int {
+            value += 1
+            return value
+        }
+
+        expect(testFunction()).toEventually(satisfyAllOf(equal(1), equal(1)))
+    }
 }