Add test for csp_meta_tag

actionview/test/template/csp_helper_test.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class CspHelperWithCspEnabledTest < ActionView::TestCase
+  tests ActionView::Helpers::CspHelper
+
+  def content_security_policy_nonce
+    "iyhD0Yc0W+c="
+  end
+
+  def content_security_policy?
+    true
+  end
+
+  def test_csp_meta_tag
+    assert_equal "<meta name=\"csp-nonce\" content=\"iyhD0Yc0W+c=\" />", csp_meta_tag
+  end
+end
+
+class CspHelperWithCspDisabledTest < ActionView::TestCase
+  tests ActionView::Helpers::CspHelper
+
+  def content_security_policy?
+    false
+  end
+
+  def test_csp_meta_tag
+    assert_nil csp_meta_tag
+  end
+end