Fix tables in call to action

Tables must have a leading and trailing blank line in markdown. Stripping the
body of a call to action means that these are missing and tables do not render
as expected.

Therefore reinstating the blank line either side of a table contained
with a CTA.

Author: brucebolt

lib/govspeak.rb

@@ -278,7 +278,7 @@ def render_image(image)
     extension("call-to-action", surrounded_by("$CTA")) do |body|
       <<~BODY
         <div class="call-to-action" markdown="1">
-        #{body.strip}
+        #{body.strip.gsub(/\A^\|/, "\n|").gsub(/\|$\Z/, "|\n")}
         </div>
       BODY
     end

test/govspeak_test.rb

@@ -467,6 +467,65 @@ class GovspeakTest < Minitest::Test
       <p>Here is some text</p>)
   end
 
+  test_given_govspeak "
+      $CTA
+      |Heading 1|Heading 2|
+      |-|-|
+      |information|more information|
+      $CTA" do
+    assert_html_output %(
+        <div class="call-to-action">
+
+        <table>
+          <thead>
+            <tr>
+              <th scope="col">Heading 1</th>
+              <th scope="col">Heading 2</th>
+            </tr>
+          </thead>
+          <tbody>
+            <tr>
+              <td>information</td>
+              <td>more information</td>
+            </tr>
+          </tbody>
+        </table>
+
+      </div>)
+  end
+
+  test_given_govspeak "
+    $CTA
+
+    ### A heading within the CTA
+
+    |Heading 1|Heading 2|
+    |-|-|
+    |information|more information|
+
+    $CTA" do
+    assert_html_output %(
+    <div class="call-to-action">
+    <h3 id="a-heading-within-the-cta">A heading within the CTA</h3>
+
+    <table>
+      <thead>
+        <tr>
+          <th scope="col">Heading 1</th>
+          <th scope="col">Heading 2</th>
+        </tr>
+      </thead>
+      <tbody>
+        <tr>
+          <td>information</td>
+          <td>more information</td>
+        </tr>
+      </tbody>
+    </table>
+
+  </div>)
+  end
+
   test_given_govspeak "
     Here is some text\n