Added back closehtml filter and test case that demonstrates it

Author: asegal-hs

src/main/java/com/hubspot/jinjava/lib/filter/CloseHtmlFilter.java

@@ -0,0 +1,28 @@
+package com.hubspot.jinjava.lib.filter;
+
+import com.hubspot.jinjava.doc.annotations.JinjavaDoc;
+import com.hubspot.jinjava.doc.annotations.JinjavaParam;
+import com.hubspot.jinjava.doc.annotations.JinjavaSnippet;
+import com.hubspot.jinjava.interpret.JinjavaInterpreter;
+
+@JinjavaDoc(
+  value = "Closes open HTML tags in a string",
+  input = @JinjavaParam(value = "s", desc = "String to close", required = true),
+  snippets = { @JinjavaSnippet(code = "{{ \"<p> Hello, world\"|closehtml }}") }
+)
+public class CloseHtmlFilter implements Filter {
+
+  @Override
+  public String getName() {
+    return "closehtml";
+  }
+
+  @Override
+  public Object filter(Object var, JinjavaInterpreter interpreter, String... args) {
+    /*
+    Closes open HTML tags.
+     */
+
+    return null;
+  }
+}

src/test/java/com/hubspot/jinjava/lib/filter/RenderFilterTest.java

@@ -49,4 +49,13 @@ public void itCountsHtmlTags() {
     assertThat(filter.filter(stringToRender, interpreter, "15"))
       .isEqualTo("<p>Hello</p>");
   }
+
+  @Test
+  public void itDoesNotAlwaysCompleteHtmlTags() {
+    String stringToRender =
+      "<p> Hello, {% if null %}world{% else %}world!{% endif %} </p>";
+
+    assertThat(filter.filter(stringToRender, interpreter, "17"))
+      .isEqualTo("<p> Hello, world!");
+  }
 }