Add test dependency on CwlPreconditionTesting

CwlPreconditionTesting allows us to unit test traps (i.e. fatalError,
assert, precondition). We currently don't have any way to test these in
the repo, so engineers simply don't test our assertions. This will
improve the overall state of our unit tests by encouraging testing of
more code paths.

Further reading on how CwlPreconditionTesting works: https://www.cocoawithlove.com/blog/2016/02/02/partial-functions-part-two-catching-precondition-failures.html

Tuist/ProjectDescriptionHelpers/Tuist+Stripe.swift

@@ -12,6 +12,7 @@ extension Project {
         public var includesSnapshots: Bool = false
         public var usesMocks: Bool = false
         public var usesStubs: Bool = false
+        public var usesPreconditionTesting: Bool = false
 
         /// Creates a `TestOptions` instance.
         ///
@@ -28,6 +29,8 @@ extension Project {
         ///     If `true`, the OCMock package will be linked.
         ///   - usesStubs: Whether the tests in this target use stubs.
         ///     If `true`, the OHHTTPStubs package will be linked.
+        ///   - usesPreconditionTesting: Whether the tests in this target uses precondition, assert, and/or fatal error testing.
+        ///     If `true`, the CwlPreconditionTesting package will be linked.
         /// - Returns: A `TestOptions` instance.
         public static func testOptions(
             resources: ResourceFileElements? = nil,
@@ -37,15 +40,17 @@ extension Project {
             ),
             includesSnapshots: Bool = false,
             usesMocks: Bool = false,
-            usesStubs: Bool = false
+            usesStubs: Bool = false,
+            usesPreconditionTesting: Bool = false
         ) -> TestOptions {
             return TestOptions(
                 resources: resources,
                 dependencies: dependencies,
                 settings: settings,
                 includesSnapshots: includesSnapshots,
                 usesMocks: usesMocks,
-                usesStubs: usesStubs
+                usesStubs: usesStubs,
+                usesPreconditionTesting: usesPreconditionTesting
             )
         }
     }
@@ -160,6 +165,7 @@ extension Project {
                 )
             )
         }
+
         if testUtilsOptions?.usesMocks ?? false
             || unitTestOptions?.usesMocks ?? false
             || uiTestOptions?.usesMocks ?? false
@@ -168,6 +174,7 @@ extension Project {
                 .remote(url: "https://github.com/erikdoe/ocmock", requirement: .branch("master"))
             )
         }
+
         if testUtilsOptions?.usesStubs ?? false
             || unitTestOptions?.usesStubs ?? false
             || uiTestOptions?.usesStubs ?? false
@@ -179,6 +186,19 @@ extension Project {
                 )
             )
         }
+
+        if testUtilsOptions?.usesPreconditionTesting ?? false
+            || unitTestOptions?.usesPreconditionTesting ?? false
+            || uiTestOptions?.usesPreconditionTesting ?? false
+        {
+            packages.append(
+                .remote(
+                    url: "https://github.com/mattgallagher/CwlPreconditionTesting",
+                    requirement: .upToNextMajor(from: "2.1.2")
+                )
+            )
+        }
+
         return packages
     }
 
@@ -301,6 +321,10 @@ extension Project {
                 .package(product: "OHHTTPStubsSwift"),
             ]
         }
+        if testOptions.usesPreconditionTesting {
+            dependencies.append(.package(product: "CwlPreconditionTesting"))
+        }
+
         return dependencies + testOptions.dependencies
     }