Add test for hasher constant accross executions

Author: nerdsupremacist

Tests/iOS/Tests/Extensions/Hasher+constantAccrossExecutions+Tests.swift

@@ -0,0 +1,12 @@
+import XCTest
+@testable import Cache
+
+final class HasherConstantAccrossExecutionsTests: XCTestCase {
+  func testHashValueRemainsTheSameAsLastTime() {
+    // Warning: this test may start failing after a Swift Update
+    let value = "some string with some values"
+    var hasher = Hasher.constantAccrossExecutions()
+    value.hash(into: &hasher)
+    XCTAssertEqual(hasher.finalize(), -4706942985426845298)
+  }
+}