Add examples of named snapshots

.travis.yml

@@ -5,3 +5,7 @@ cache: bundler
 rvm:
   - 2.6.3
 before_install: gem install bundler -v 2.0.2
+
+script:
+  - bundle exec rspec
+  - bundle exec rake examples

examples/__snapshots__/named.minitest.spec.txt

@@ -0,0 +1 @@
+named

examples/__snapshots__/named.minitest.test.txt

@@ -0,0 +1 @@
+named

examples/__snapshots__/named.rspec.txt

@@ -0,0 +1 @@
+named

examples/__snapshots__/named.unit.txt

@@ -0,0 +1 @@
+named

examples/minitest.rb

@@ -9,13 +9,21 @@ def test_snapshot
     assert_snapshot "hello"
     assert_snapshot "goodbye"
   end
+
+  def test_named_snapshot
+    assert_snapshot "named.minitest.test.txt", "named"
+  end
 end
 
 class ExampleSpec < Minitest::Spec
   include SnapshotTesting::Minitest
 
   it "takes a snapshot" do
-    "hello".must_match_snapshot
-    "goodbye".must_match_snapshot
+    _("hello").must_match_snapshot
+    _("goodbye").must_match_snapshot
+  end
+
+  it "takes a named snapshot" do
+    _("named").must_match_snapshot "named.minitest.spec.txt"
   end
 end

examples/rspec.rb

@@ -11,4 +11,8 @@
     expect("hello").to match_snapshot
     expect("goodbye").to match_snapshot
   end
+
+  it "takes a named snapshot" do
+    expect("named").to match_snapshot("named.rspec.txt")
+  end
 end

examples/test_unit.rb

@@ -9,4 +9,8 @@ def test_snapshot
     assert_snapshot "hello"
     assert_snapshot "goodbye"
   end
+
+  def test_named_snapshot
+    assert_snapshot "named.unit.txt", "named"
+  end
 end

lib/snapshot_testing/minitest.rb

@@ -5,7 +5,7 @@ module Minitest
     def self.included(_)
       return unless defined?(::Minitest::Expectations)
       return if ::Minitest::Expectations.method_defined?(:must_match_snapshot)
-      ::Minitest::Expectations.infect_an_assertion(:assert_snapshot, :must_match_snapshot, true)
+      ::Minitest::Expectations.infect_an_assertion(:assert_snapshot, :must_match_snapshot)
     end
 
     def before_setup