diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index 4f4d9f7..c7c2137 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -24,13 +24,13 @@ jobs:
     - name: checkout
       uses: actions/checkout@v2
     - name: simple test
-      run: go test -v ./ -count=1
+      run: go test -v ./... -count=1
     - name: test with GC pressure
-      run: go test -v ./ -count=1
+      run: go test -v ./... -count=1
       env:
         GOGC: 1
     - name: test with race detector
-      run: go test -v -race ./ -count=1
+      run: go test -v -race ./... -count=1
   bench:
     name: Benchmark
     runs-on: ubuntu-latest
diff --git a/Makefile b/Makefile
index fd49bb1..363563a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 PKG := github.com/goccy/go-json
 
 BIN_DIR := $(CURDIR)/bin
-PKGS := $(shell go list ./... | grep -v internal/cmd)
+PKGS := $(shell go list ./... | grep -v internal/cmd|grep -v test)
 COVER_PKGS := $(foreach pkg,$(PKGS),$(subst $(PKG),.,$(pkg)))
 
 COMMA := ,
@@ -14,7 +14,7 @@ $(BIN_DIR):
 
 .PHONY: cover
 cover:
-	go test -coverpkg=$(COVERPKG_OPT) -coverprofile=cover.out .
+	go test -coverpkg=$(COVERPKG_OPT) -coverprofile=cover.out ./...
 
 .PHONY: cover-html
 cover-html: cover
diff --git a/cover_array_test.go b/test/cover/cover_array_test.go
similarity index 100%
rename from cover_array_test.go
rename to test/cover/cover_array_test.go
diff --git a/cover_bool_test.go b/test/cover/cover_bool_test.go
similarity index 100%
rename from cover_bool_test.go
rename to test/cover/cover_bool_test.go
diff --git a/cover_bytes_test.go b/test/cover/cover_bytes_test.go
similarity index 100%
rename from cover_bytes_test.go
rename to test/cover/cover_bytes_test.go
diff --git a/cover_float32_test.go b/test/cover/cover_float32_test.go
similarity index 100%
rename from cover_float32_test.go
rename to test/cover/cover_float32_test.go
diff --git a/cover_float64_test.go b/test/cover/cover_float64_test.go
similarity index 100%
rename from cover_float64_test.go
rename to test/cover/cover_float64_test.go
diff --git a/cover_helper_test.go b/test/cover/cover_helper_test.go
similarity index 100%
rename from cover_helper_test.go
rename to test/cover/cover_helper_test.go
diff --git a/cover_int16_test.go b/test/cover/cover_int16_test.go
similarity index 100%
rename from cover_int16_test.go
rename to test/cover/cover_int16_test.go
diff --git a/cover_int32_test.go b/test/cover/cover_int32_test.go
similarity index 100%
rename from cover_int32_test.go
rename to test/cover/cover_int32_test.go
diff --git a/cover_int64_test.go b/test/cover/cover_int64_test.go
similarity index 100%
rename from cover_int64_test.go
rename to test/cover/cover_int64_test.go
diff --git a/cover_int8_test.go b/test/cover/cover_int8_test.go
similarity index 100%
rename from cover_int8_test.go
rename to test/cover/cover_int8_test.go
diff --git a/cover_int_test.go b/test/cover/cover_int_test.go
similarity index 100%
rename from cover_int_test.go
rename to test/cover/cover_int_test.go
diff --git a/cover_map_test.go b/test/cover/cover_map_test.go
similarity index 100%
rename from cover_map_test.go
rename to test/cover/cover_map_test.go
diff --git a/cover_marshal_json_test.go b/test/cover/cover_marshal_json_test.go
similarity index 100%
rename from cover_marshal_json_test.go
rename to test/cover/cover_marshal_json_test.go
diff --git a/cover_marshal_text_test.go b/test/cover/cover_marshal_text_test.go
similarity index 100%
rename from cover_marshal_text_test.go
rename to test/cover/cover_marshal_text_test.go
diff --git a/cover_number_test.go b/test/cover/cover_number_test.go
similarity index 100%
rename from cover_number_test.go
rename to test/cover/cover_number_test.go
diff --git a/cover_slice_test.go b/test/cover/cover_slice_test.go
similarity index 100%
rename from cover_slice_test.go
rename to test/cover/cover_slice_test.go
diff --git a/cover_string_test.go b/test/cover/cover_string_test.go
similarity index 100%
rename from cover_string_test.go
rename to test/cover/cover_string_test.go
diff --git a/cover_uint16_test.go b/test/cover/cover_uint16_test.go
similarity index 100%
rename from cover_uint16_test.go
rename to test/cover/cover_uint16_test.go
diff --git a/cover_uint32_test.go b/test/cover/cover_uint32_test.go
similarity index 100%
rename from cover_uint32_test.go
rename to test/cover/cover_uint32_test.go
diff --git a/cover_uint64_test.go b/test/cover/cover_uint64_test.go
similarity index 100%
rename from cover_uint64_test.go
rename to test/cover/cover_uint64_test.go
diff --git a/cover_uint8_test.go b/test/cover/cover_uint8_test.go
similarity index 100%
rename from cover_uint8_test.go
rename to test/cover/cover_uint8_test.go
diff --git a/cover_uint_test.go b/test/cover/cover_uint_test.go
similarity index 100%
rename from cover_uint_test.go
rename to test/cover/cover_uint_test.go
diff --git a/example_marshaling_test.go b/test/example/example_marshaling_test.go
similarity index 100%
rename from example_marshaling_test.go
rename to test/example/example_marshaling_test.go
diff --git a/example_test.go b/test/example/example_test.go
similarity index 100%
rename from example_test.go
rename to test/example/example_test.go
diff --git a/example_text_marshaling_test.go b/test/example/example_text_marshaling_test.go
similarity index 100%
rename from example_text_marshaling_test.go
rename to test/example/example_text_marshaling_test.go