add test for schema and builder

internal/closter/events/build.go

@@ -76,7 +76,7 @@ func (b *Builder) Release() {
 
 func (b *Builder) Write(list *v1.List) arrow.Record {
 	ls := list.GetItems()
-	sort.Slice(ls, func(i, j int) bool {
+	sort.SliceStable(ls, func(i, j int) bool {
 		return ls[i].Timestamp < ls[j].Timestamp
 	})
 	b.r.Reserve(len(ls))

internal/closter/events/build_test.go

@@ -13,17 +13,20 @@ func TestBuild(t *testing.T) {
 	b := New(memory.NewGoAllocator())
 	defer b.Release()
 
-	b.Write(&v1.List{
+	r := b.Write(&v1.List{
 		Items: []*v1.Data{
 			{Bounce: nil},
 			{Bounce: True},
 			{Bounce: False},
 			{Page: "/"},
 		},
 	})
-	r := b.NewRecord()
 	got, _ := r.MarshalJSON()
 	// os.WriteFile("testdata/record.json", got, 0600)
 	want, _ := os.ReadFile("testdata/record.json")
-	require.Equal(t, string(want), string(got))
+	require.JSONEq(t, string(want), string(got))
+	gotSchema := r.Schema().String()
+	// os.WriteFile("testdata/schema.txt", []byte(gotSchema), 0600)
+	wantSchema, _ := os.ReadFile("testdata/schema.txt")
+	require.Equal(t, string(wantSchema), gotSchema)
 }

internal/closter/events/testdata/record.json

@@ -1,5 +1,5 @@
-[{"bounce":null,"browser":null,"browser_version":null,"city":null,"country":null,"device":null,"domain":null,"duration":0,"entry_page":null,"event":null,"exit_page":null,"id":0,"os":null,"os_version":null,"page":null,"referrer":null,"region":null,"session":false,"source":null,"timestamp":0,"utm_campaign":null,"utm_content":null,"utm_medium":null,"utm_source":null,"utm_term":null,"view":false}
-,{"bounce":true,"browser":null,"browser_version":null,"city":null,"country":null,"device":null,"domain":null,"duration":0,"entry_page":null,"event":null,"exit_page":null,"id":0,"os":null,"os_version":null,"page":null,"referrer":null,"region":null,"session":false,"source":null,"timestamp":0,"utm_campaign":null,"utm_content":null,"utm_medium":null,"utm_source":null,"utm_term":null,"view":false}
-,{"bounce":false,"browser":null,"browser_version":null,"city":null,"country":null,"device":null,"domain":null,"duration":0,"entry_page":null,"event":null,"exit_page":null,"id":0,"os":null,"os_version":null,"page":null,"referrer":null,"region":null,"session":false,"source":null,"timestamp":0,"utm_campaign":null,"utm_content":null,"utm_medium":null,"utm_source":null,"utm_term":null,"view":false}
-,{"bounce":null,"browser":null,"browser_version":null,"city":null,"country":null,"device":null,"domain":null,"duration":0,"entry_page":null,"event":null,"exit_page":null,"id":0,"os":null,"os_version":null,"page":"/","referrer":null,"region":null,"session":false,"source":null,"timestamp":0,"utm_campaign":null,"utm_content":null,"utm_medium":null,"utm_source":null,"utm_term":null,"view":false}
+[{"bounce":null,"browser":null,"browser_version":null,"city":null,"country":null,"device":null,"domain":null,"duration":0,"entry_page":null,"event":null,"exit_page":null,"host":null,"id":0,"os":null,"os_version":null,"page":null,"referrer":null,"region":null,"session":false,"source":null,"timestamp":0,"utm_campaign":null,"utm_content":null,"utm_medium":null,"utm_source":null,"utm_term":null,"view":false}
+,{"bounce":true,"browser":null,"browser_version":null,"city":null,"country":null,"device":null,"domain":null,"duration":0,"entry_page":null,"event":null,"exit_page":null,"host":null,"id":0,"os":null,"os_version":null,"page":null,"referrer":null,"region":null,"session":false,"source":null,"timestamp":0,"utm_campaign":null,"utm_content":null,"utm_medium":null,"utm_source":null,"utm_term":null,"view":false}
+,{"bounce":false,"browser":null,"browser_version":null,"city":null,"country":null,"device":null,"domain":null,"duration":0,"entry_page":null,"event":null,"exit_page":null,"host":null,"id":0,"os":null,"os_version":null,"page":null,"referrer":null,"region":null,"session":false,"source":null,"timestamp":0,"utm_campaign":null,"utm_content":null,"utm_medium":null,"utm_source":null,"utm_term":null,"view":false}
+,{"bounce":null,"browser":null,"browser_version":null,"city":null,"country":null,"device":null,"domain":null,"duration":0,"entry_page":null,"event":null,"exit_page":null,"host":null,"id":0,"os":null,"os_version":null,"page":"/","referrer":null,"region":null,"session":false,"source":null,"timestamp":0,"utm_campaign":null,"utm_content":null,"utm_medium":null,"utm_source":null,"utm_term":null,"view":false}
 ]

internal/closter/events/testdata/schema.txt

@@ -0,0 +1,29 @@
+schema:
+  fields: 27
+    - timestamp: type=int64
+    - id: type=int64
+    - bounce: type=bool, nullable
+    - session: type=bool
+    - view: type=bool
+    - duration: type=float64
+    - event: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - page: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - entry_page: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - exit_page: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - source: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - referrer: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - utm_source: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - utm_medium: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - utm_campaign: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - utm_content: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - utm_term: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - device: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - browser: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - browser_version: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - os: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - os_version: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - country: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - region: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - domain: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - city: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable
+    - host: type=dictionary<values=utf8, indices=uint32, ordered=false>, nullable