diff --git a/pkg/grammar/functions_test.go b/pkg/grammar/functions_test.go
new file mode 100644
index 00000000..6e8a56ed
--- /dev/null
+++ b/pkg/grammar/functions_test.go
@@ -0,0 +1,63 @@
+package grammar_test
+
+import (
+	. "github.com/go-skynet/LocalAI/pkg/grammar"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("LocalAI grammar functions", func() {
+	Describe("ToJSONStructure()", func() {
+		It("converts a list of functions to a JSON structure that can be parsed to a grammar", func() {
+			var functions Functions = []Function{
+				{
+					Name: "create_event",
+					Parameters: map[string]interface{}{
+						"properties": map[string]interface{}{
+							"event_name": map[string]interface{}{
+								"type": "string",
+							},
+							"event_date": map[string]interface{}{
+								"type": "string",
+							},
+						},
+					},
+				},
+				{
+					Name: "search",
+					Parameters: map[string]interface{}{
+						"properties": map[string]interface{}{
+							"query": map[string]interface{}{
+								"type": "string",
+							},
+						},
+					},
+				},
+			}
+
+			js := functions.ToJSONStructure()
+			Expect(len(js.OneOf)).To(Equal(2))
+			Expect(js.OneOf[0].Properties.Function.Const).To(Equal("create_event"))
+			Expect(js.OneOf[0].Properties.Arguments.Properties["event_name"].(map[string]interface{})["type"]).To(Equal("string"))
+			Expect(js.OneOf[0].Properties.Arguments.Properties["event_date"].(map[string]interface{})["type"]).To(Equal("string"))
+			Expect(js.OneOf[1].Properties.Function.Const).To(Equal("search"))
+			Expect(js.OneOf[1].Properties.Arguments.Properties["query"].(map[string]interface{})["type"]).To(Equal("string"))
+		})
+	})
+	Context("Select()", func() {
+		It("selects one of the functions and returns a list containing only the selected one", func() {
+			var functions Functions = []Function{
+				{
+					Name: "create_event",
+				},
+				{
+					Name: "search",
+				},
+			}
+
+			functions = functions.Select("create_event")
+			Expect(len(functions)).To(Equal(1))
+			Expect(functions[0].Name).To(Equal("create_event"))
+		})
+	})
+})