Adds some tests to DruidFilterInfo.

--Also fixes a few edge cases that came up from the tests (we weren't
handling `null` correctly, and the `NotFilter` is not in fact a
MulticlauseFilter despite having a child).

--Also fixes a test that started failing `AsyncInvalidApiRequest`. It
was using the `GroovyTestUtils::compareJson` rather than
`GroovyTestUtils::compareErrorPayload` which does something very
similar, except it ignores the `requestId`. I don't know why this test
wasn't failing earlier.

fili-core/src/main/java/com/yahoo/bard/webservice/logging/blocks/DruidFilterInfo.java

@@ -3,13 +3,15 @@
 package com.yahoo.bard.webservice.logging.blocks;
 
 import com.yahoo.bard.webservice.druid.model.filter.MultiClauseFilter;
+import com.yahoo.bard.webservice.druid.model.filter.NotFilter;
 import com.yahoo.bard.webservice.logging.LogInfo;
 
 import com.fasterxml.jackson.annotation.JsonAutoDetect;
 
 import com.yahoo.bard.webservice.druid.model.filter.Filter;
 
 import java.util.ArrayDeque;
+import java.util.Collections;
 import java.util.Deque;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -41,6 +43,9 @@ public DruidFilterInfo(Filter filter) {
      * @return A map containing a count of each type of filter
      */
     private Map<String, Long> buildFilterCount(Filter filter) {
+        if (filter == null) {
+            return Collections.emptyMap();
+        }
         Map<String, Long> filterTypeCounter = new LinkedHashMap<>();
         Deque<Filter> filterStack = new ArrayDeque<>();
         filterStack.add(filter);
@@ -52,6 +57,8 @@ private Map<String, Long> buildFilterCount(Filter filter) {
             );
             if (currentFilter instanceof MultiClauseFilter) {
                 filterStack.addAll(((MultiClauseFilter) currentFilter).getFields());
+            } else if (currentFilter instanceof NotFilter) {
+                filterStack.add(((NotFilter) currentFilter).getField());
             }
         }
         return filterTypeCounter;

fili-core/src/test/groovy/com/yahoo/bard/webservice/async/AsyncInvalidApiRequest.groovy

@@ -37,7 +37,8 @@ class AsyncInvalidApiRequest extends AsyncFunctionalSpec {
 
     @Override
     Map<String, Closure<Void>> getResultAssertions() {
-        [ data: { assert GroovyTestUtils.compareJson(it.readEntity(String), EXPECTED_ERROR_MESSAGE) } ]
+        [ data: { assert GroovyTestUtils.compareErrorPayload(it.readEntity(String), EXPECTED_ERROR_MESSAGE) } ]
+
     }
 
     @Override

fili-core/src/test/groovy/com/yahoo/bard/webservice/logging/blocks/DruidFilterInfoSpec.groovy

@@ -0,0 +1,37 @@
+package com.yahoo.bard.webservice.logging.blocks
+
+import com.yahoo.bard.webservice.data.dimension.Dimension
+import com.yahoo.bard.webservice.druid.model.filter.AndFilter
+import com.yahoo.bard.webservice.druid.model.filter.Filter
+import com.yahoo.bard.webservice.druid.model.filter.NotFilter
+import com.yahoo.bard.webservice.druid.model.filter.OrFilter
+import com.yahoo.bard.webservice.druid.model.filter.SelectorFilter
+
+import spock.lang.Shared
+import spock.lang.Specification
+import spock.lang.Unroll
+
+
+class DruidFilterInfoSpec extends Specification {
+
+    @Shared Filter selector = new SelectorFilter(Stub(Dimension), "value")
+
+    static final String SELECTOR_NAME = SelectorFilter.class.simpleName
+    static final String AND_NAME = AndFilter.class.simpleName
+    static final String OR_NAME = OrFilter.class.simpleName
+    static final String NOT_NAME = NotFilter.class.simpleName
+
+    @Unroll
+    def "The DruidFilterInfo correctly analyzes #filter"() {
+        expect:
+        new DruidFilterInfo(filter).numEachFilterType == expectedMap
+
+        where:
+        filter                                                                                                  | expectedMap
+        null                                                                                                    | [:]
+        selector                                                                                                | [(SELECTOR_NAME): 1L]
+        new AndFilter([selector, selector])                                                                     | [(AND_NAME): 1L, (SELECTOR_NAME): 2L]
+        new NotFilter(new AndFilter([selector, selector]))                                                      | [(NOT_NAME): 1L, (AND_NAME): 1L, (SELECTOR_NAME): 2L]
+        new OrFilter([new AndFilter([selector, selector]), new NotFilter(new AndFilter([selector, selector]))]) | [(OR_NAME): 1L, (AND_NAME): 2L, (NOT_NAME): 1L, (SELECTOR_NAME): 4L]
+    }
+}