Remove hardcoded key-dependent values from tests

Because these hardcoded values make the tests fail when recreating the keys.
This is not convenient.

* Remove hardcoded subjectKeyIdentifier value assertions.
* In test_sign, replace assertion with hardcoded value with
  PRIVATE_KEY.verify (OpenSSL::PKey::RSA#verify) to assert
  signature

Assisted-by: Claude:claude-opus-4-6[1m]

Author: junaruga

test/rubygems/test_gem_security.rb

@@ -46,8 +46,6 @@ def test_class_create_cert
 
     key_ident = cert.extensions.find {|ext| ext.oid == "subjectKeyIdentifier" }
     assert_equal 59, key_ident.value.length
-    assert_equal "B1:1A:54:09:67:45:60:02:02:D7:CE:F4:1D:60:4A:89:DF:E7:58:D9",
-                 key_ident.value
 
     assert_equal "", cert.issuer.to_s
     assert_equal name.to_s, cert.subject.to_s
@@ -94,8 +92,6 @@ def test_class_create_cert_email
 
     key_ident = cert.extensions.find {|ext| ext.oid == "subjectKeyIdentifier" }
     assert_equal 59, key_ident.value.length
-    assert_equal "B1:1A:54:09:67:45:60:02:02:D7:CE:F4:1D:60:4A:89:DF:E7:58:D9",
-                 key_ident.value
   end
 
   def test_class_create_key
@@ -225,8 +221,6 @@ def test_class_sign
     key_ident =
       signed.extensions.find {|ext| ext.oid == "subjectKeyIdentifier" }
     assert_equal 59, key_ident.value.length
-    assert_equal "B1:1A:54:09:67:45:60:02:02:D7:CE:F4:1D:60:4A:89:DF:E7:58:D9",
-                 key_ident.value
 
     assert signed.verify key
   end
@@ -267,8 +261,6 @@ def test_class_sign_AltName
     key_ident =
       signed.extensions.find {|ext| ext.oid == "subjectKeyIdentifier" }
     assert_equal 59, key_ident.value.length
-    assert_equal "B1:1A:54:09:67:45:60:02:02:D7:CE:F4:1D:60:4A:89:DF:E7:58:D9",
-                 key_ident.value
 
     assert signed.verify PUBLIC_KEY
   end

test/rubygems/test_gem_security_signer.rb

@@ -120,16 +120,8 @@ def test_sign
 
     signature = signer.sign "hello"
 
-    expected = <<-EXPECTED
-FmrCYxEXW3dgYYNMxPdS16VrdXT+d5nyXTVlRm64ZHSgMxMAaPtQJsVYv73m
-DWHTzNnLhhINSpgBMLh5a4atM52yxVdkPUTgqIH+LeIPBXn8xaP5JLmfDcmI
-tBpc/9DhS3v9iKCX40igAArFu7Gg3swbgQ61SP+U22LvG5nDQZQz3sudtsw3
-qKPykFVaYjrRwzvBdSdJ1PwlAsanSwcwS/GKPtmE/ykZ6X5XOx7wvCDL/zGy
-B8khkB8hDKC6moCzebmUxCBmTmXD0Wjzon+bf4MOriVE3a0ySGRvpr1mKR2+
-9EaVo7pDJLEM487+xg1CAZHRhwshd6II00XEzG/jBQ==
-    EXPECTED
-
-    assert_equal expected, [signature].pack("m")
+    digest = OpenSSL::Digest.new(Gem::Security::DIGEST_NAME)
+    assert PRIVATE_KEY.verify(digest, signature, "hello")
   end
 
   def test_sign_expired