Fix serialization of suggester with context queries

Context queries of a suggester need to be serializes as a dictionary,
not an array.

See #329

CONTRIBUTORS

@@ -59,3 +59,4 @@ TimeEmit [@TimeEmit](https://github.com/timeemit)
 TusharM [@tusharm](https://github.com/tusharm)
 wolfkdy [@wolfkdy](https://github.com/wolfkdy)
 zakthomas [@zakthomas](https://github.com/zakthomas)
+singham [@zhaochenxiao90](https://github.com/zhaochenxiao90)

client.go

@@ -21,7 +21,7 @@ import (
 
 const (
 	// Version is the current version of Elastic.
-	Version = "2.0.51"
+	Version = "2.0.52"
 
 	// DefaultUrl is the default endpoint of Elasticsearch on the local machine.
 	// It is used e.g. when initializing a new Client without a specific URL.

suggester_completion.go

@@ -102,9 +102,18 @@ func (q CompletionSuggester) Source(includeName bool) interface{} {
 	case 1:
 		suggester["context"] = q.contextQueries[0].Source()
 	default:
-		ctxq := make([]interface{}, 0)
+		ctxq := make(map[string]interface{})
 		for _, query := range q.contextQueries {
-			ctxq = append(ctxq, query.Source())
+			src := query.Source()
+			// Merge the dictionary into ctxq
+			m, ok := src.(map[string]interface{})
+			if !ok {
+				// We have no way of reporting errors in v2, so we just swallow it.
+				continue
+			}
+			for k, v := range m {
+				ctxq[k] = v
+			}
 		}
 		suggester["context"] = ctxq
 	}

suggester_completion_test.go

@@ -23,3 +23,22 @@ func TestCompletionSuggesterSource(t *testing.T) {
 		t.Errorf("expected\n%s\n,got:\n%s", expected, got)
 	}
 }
+
+func TestCompletionSuggesterSourceWithMultipleContexts(t *testing.T) {
+	s := NewCompletionSuggester("song-suggest").
+		Text("n").
+		Field("suggest").
+		ContextQueries(
+			NewSuggesterCategoryQuery("artist", "Sting"),
+			NewSuggesterCategoryQuery("label", "BMG"),
+		)
+	data, err := json.Marshal(s.Source(true))
+	if err != nil {
+		t.Fatalf("marshaling to JSON failed: %v", err)
+	}
+	got := string(data)
+	expected := `{"song-suggest":{"text":"n","completion":{"context":{"artist":"Sting","label":"BMG"},"field":"suggest"}}}`
+	if got != expected {
+		t.Errorf("expected\n%s\n,got:\n%s", expected, got)
+	}
+}