update unit test to be compatible with new source_location format

test/unit/environment_filter_test.rb

@@ -36,14 +36,14 @@ class EnvironmentFilterTest < Minitest::Test
     assert_equal("public", strainer.invoke("public_filter"))
   end
 
-  def test_stainer_raises_argument_error
+  def test_strainer_raises_argument_error
     strainer = @environment.create_strainer(@context)
     assert_raises(Liquid::ArgumentError) do
       strainer.invoke("public_filter", 1)
     end
   end
 
-  def test_stainer_argument_error_contains_backtrace
+  def test_strainer_argument_error_contains_backtrace
     strainer = @environment.create_strainer(@context)
 
     exception = assert_raises(Liquid::ArgumentError) do
@@ -54,8 +54,9 @@ class EnvironmentFilterTest < Minitest::Test
       /\ALiquid error: wrong number of arguments \((1 for 0|given 1, expected 0)\)\z/,
       exception.message,
     )
+
     source = AccessScopeFilters.instance_method(:public_filter).source_location
-    assert_equal(source.map(&:to_s), exception.backtrace[0].split(':')[0..1])
+    assert_equal(source[0..1].map(&:to_s), exception.backtrace[0].split(':')[0..1])
   end
 
   def test_strainer_only_invokes_public_filter_methods