fixes for not found scenarios

core/src/main/groovy/com/muwire/core/search/SearchIndex.groovy

@@ -22,7 +22,7 @@ class SearchIndex {
 		Set<String> rv = null;
 		
 		terms.each {
-			Set<String> forWord = keywords.get it
+			Set<String> forWord = keywords.getOrDefault(it,[])
 			if (rv == null) {
 				rv = forWord
 			} else {
@@ -31,6 +31,8 @@ class SearchIndex {
 				
 		}
 		
-		rv.asList()
+		if (rv != null)
+			return rv.asList()
+		[]
 	}
 }

core/src/test/groovy/com/muwire/core/search/SearchIndexTest.groovy

@@ -40,4 +40,19 @@ class SearchIndexTest {
 		assert found.size() == 1
 		assert found.contains("c d.e")
 	}
+	
+	@Test
+	void testNotFound() {
+		initIndex(["a b.c"])
+		def found = index.search(["d"])
+		assert found.size() == 0
+	}
+	
+	@Test
+	void testSomeNotFound() {
+		initIndex(["a b.c"])
+		def found = index.search(["a","d"])
+		assert found.size() == 0
+		
+	}
 }