Merge pull request #15269 from lorentey/static-snow

[test] Merge hash determinism/randomisation tests

Author: lorentey

validation-test/stdlib/Hashing.swift

@@ -57,10 +57,4 @@ HashingTestSuite.test("_Hasher/DefaultKey") {
   expectEqual(customHasher.finalize(), defaultHash)
 }
 
-HashingTestSuite.test("_Hasher/determinism") {
-  // By defaults, tests are configured to run with deterministic hashing.
-  expectTrue(_Hasher._isDeterministic)
-  expectEqual((0, 0), _Hasher._seed)
-}
-
 runAllTests()

validation-test/stdlib/HashingRandomization.swift

@@ -1,26 +1,35 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -module-name main %s -o %t/hash
-// RUN: (export -n %env-SWIFT_DETERMINISTIC_HASHING; %target-run %t/hash && %target-run %t/hash) | %FileCheck %s
-// REQUIRES: executable_test
+// RUN: (export -n %env-SWIFT_DETERMINISTIC_HASHING; %target-run %t/hash && %target-run %t/hash) | %FileCheck --check-prefixes=RANDOM %s
+// RUN: (export %env-SWIFT_DETERMINISTIC_HASHING=1; %target-run %t/hash && %target-run %t/hash) | %FileCheck --check-prefixes=STABLE %s
 
 // This check verifies that the hash seed is randomly generated on every
-// execution of a Swift program. There is a minuscule chance that the same seed
-// is generated on two separate executions; however, a test failure here is more
-// likely to indicate an issue with the random number generator or the testing
-// environment.
+// execution of a Swift program unless the SWIFT_DETERMINISTIC_HASHING
+// environment variable is set.
 
 print("Deterministic: \(_Hasher._isDeterministic)")
 print("Seed: \(_Hasher._seed)")
 print("Hash values: <\(0.hashValue), \(1.hashValue)>")
 
-// On the first run, remember the seed and hash value.
-//   CHECK: Deterministic: false
-//   CHECK-NEXT: Seed: [[SEED0:\([0-9]+, [0-9]+\)]]
-//   CHECK-NEXT: Hash values: [[HASH0:<-?[0-9]+, -?[0-9]+>]]
+// With randomized hashing, we get a new seed and a new set of hash values on
+// each run. There is a minuscule chance that the same seed is generated on two
+// separate executions; however, a test failure here is more likely to indicate
+// an issue with the random number generator or the testing environment.
+//   RANDOM: Deterministic: false
+//   RANDOM-NEXT: Seed: [[SEED0:\([0-9]+, [0-9]+\)]]
+//   RANDOM-NEXT: Hash values: [[HASH0:<-?[0-9]+, -?[0-9]+>]]
+//   RANDOM-NEXT: Deterministic: false
+//   RANDOM-NEXT: Seed:
+//   RANDOM-NOT: [[SEED0]]
+//   RANDOM-NEXT: Hash values:
+//   RANDOM-NOT: [[HASH0]]
 
-// Check that the values are different on the second run.
-//   CHECK-NEXT: Deterministic: false
-//   CHECK-NEXT: Seed:
-//   CHECK-NOT: [[SEED0]]
-//   CHECK-NEXT: Hash values:
-//   CHECK-NOT: [[HASH0]]
+// Stable runs have known seeds, and generate the same hash values.  A test
+// failure here indicates that the seed override mechanism isn't working
+// correctly.
+//   STABLE: Deterministic: true
+//   STABLE-NEXT: Seed: (0, 0)
+//   STABLE-NEXT: Hash values: [[HASH1:<-?[0-9]+, -?[0-9]+>]]
+//   STABLE-NEXT: Deterministic: true
+//   STABLE-NEXT: Seed: (0, 0)
+//   STABLE-NEXT: Hash values: [[HASH1]]