test: cover MessageVerifierTest and test_round_trips_a_hash

test/test_message_verifier.rb

@@ -0,0 +1,100 @@
+require 'minitest/autorun'
+require 'prism'
+
+class MessageVerifierTest < Minitest::Test
+  def setup
+    @verifier = Prism::MessageVerifier.new('s3cr3t')
+  end
+
+  def test_round_trips_a_hash
+    signed = @verifier.generate('user_id' => 42)
+    assert_equal({ 'user_id' => 42 }, @verifier.verify(signed))
+  end
+
+  def test_round_trips_a_string
+    signed = @verifier.generate('hello world')
+    assert_equal 'hello world', @verifier.verify(signed)
+  end
+
+  def test_tampered_payload_is_rejected
+    signed = @verifier.generate('user_id' => 1)
+    data, signature = signed.split('--', 2)
+    tampered = "#{data}x--#{signature}"
+    assert_raises(Prism::MessageVerifier::InvalidSignature) { @verifier.verify(tampered) }
+  end
+
+  def test_tampered_signature_is_rejected
+    signed = @verifier.generate('user_id' => 1)
+    data, = signed.split('--', 2)
+    assert_raises(Prism::MessageVerifier::InvalidSignature) { @verifier.verify("#{data}--deadbeef") }
+  end
+
+  def test_wrong_secret_cannot_verify
+    signed = @verifier.generate('user_id' => 1)
+    other = Prism::MessageVerifier.new('different-secret')
+    assert_raises(Prism::MessageVerifier::InvalidSignature) { other.verify(signed) }
+  end
+
+  def test_malformed_message_is_rejected
+    assert_raises(Prism::MessageVerifier::InvalidSignature) { @verifier.verify('not-a-signed-message') }
+    assert_raises(Prism::MessageVerifier::InvalidSignature) { @verifier.verify(nil) }
+  end
+
+  def test_verified_returns_nil_instead_of_raising
+    assert_nil @verifier.verified('garbage')
+  end
+
+  def test_blank_secret_is_rejected
+    assert_raises(ArgumentError) { Prism::MessageVerifier.new('') }
+    assert_raises(ArgumentError) { Prism::MessageVerifier.new(nil) }
+  end
+
+  def test_expires_at_in_the_future_still_verifies
+    signed = @verifier.generate({ 'id' => 1 }, expires_at: Time.now.utc + 60)
+    assert_equal({ 'id' => 1 }, @verifier.verify(signed))
+  end
+
+  def test_expires_at_in_the_past_is_rejected
+    signed = @verifier.generate({ 'id' => 1 }, expires_at: Time.now.utc - 1)
+    assert_raises(Prism::MessageVerifier::InvalidSignature) { @verifier.verify(signed) }
+  end
+
+  def test_expires_in_computes_expires_at_from_now
+    signed = @verifier.generate('hello', expires_in: 10)
+    assert_equal 'hello', @verifier.verify(signed)
+  end
+
+  def test_expired_message_does_not_survive_tampering_style_verification
+    signed = @verifier.generate('hello', expires_in: -1)
+    assert_nil @verifier.verified(signed)
+  end
+
+  def test_purpose_must_match_on_verify
+    signed = @verifier.generate('secret-token', purpose: 'password_reset')
+    assert_equal 'secret-token', @verifier.verify(signed, purpose: 'password_reset')
+    assert_raises(Prism::MessageVerifier::InvalidSignature) { @verifier.verify(signed, purpose: 'email_confirmation') }
+    assert_raises(Prism::MessageVerifier::InvalidSignature) { @verifier.verify(signed) }
+  end
+
+  def test_purposeless_message_rejected_when_a_purpose_is_required
+    signed = @verifier.generate('plain')
+    assert_raises(Prism::MessageVerifier::InvalidSignature) { @verifier.verify(signed, purpose: 'password_reset') }
+  end
+
+  def test_purpose_accepts_symbol_or_string_interchangeably
+    signed = @verifier.generate('value', purpose: :password_reset)
+    assert_equal 'value', @verifier.verify(signed, purpose: 'password_reset')
+  end
+
+  def test_plain_generate_still_round_trips_without_envelope_overhead
+    signed = @verifier.generate('user_id' => 1)
+    refute_includes decode_payload(signed).keys, '_prism_envelope'
+  end
+
+  private
+
+  def decode_payload(signed)
+    data, = signed.split('--', 2)
+    JSON.parse(data.unpack1('m0'))
+  end
+end