diff --git a/spec/fixtures/tags/add_input.go b/spec/fixtures/tags/add_input.go
new file mode 100644
index 0000000..7e27a27
--- /dev/null
+++ b/spec/fixtures/tags/add_input.go
@@ -0,0 +1,11 @@
+package main
+
+type Test struct {
+	ID      int
+	Name    string
+	Num     int64
+	Another struct {
+		First  int
+		Second string
+	}
+}
diff --git a/spec/fixtures/tags/add_output.go b/spec/fixtures/tags/add_output.go
new file mode 100644
index 0000000..eaba62f
--- /dev/null
+++ b/spec/fixtures/tags/add_output.go
@@ -0,0 +1,11 @@
+package main
+
+type Test struct {
+	ID      int    `json:"id"`
+	Name    string `json:"name"`
+	Num     int64  `json:"num"`
+	Another struct {
+		First  int    `json:"first"`
+		Second string `json:"second"`
+	} `json:"another"`
+}
diff --git a/spec/fixtures/tags/remove_input.go b/spec/fixtures/tags/remove_input.go
new file mode 100644
index 0000000..eaba62f
--- /dev/null
+++ b/spec/fixtures/tags/remove_input.go
@@ -0,0 +1,11 @@
+package main
+
+type Test struct {
+	ID      int    `json:"id"`
+	Name    string `json:"name"`
+	Num     int64  `json:"num"`
+	Another struct {
+		First  int    `json:"first"`
+		Second string `json:"second"`
+	} `json:"another"`
+}
diff --git a/spec/fixtures/tags/remove_output.go b/spec/fixtures/tags/remove_output.go
new file mode 100644
index 0000000..7e27a27
--- /dev/null
+++ b/spec/fixtures/tags/remove_output.go
@@ -0,0 +1,11 @@
+package main
+
+type Test struct {
+	ID      int
+	Name    string
+	Num     int64
+	Another struct {
+		First  int
+		Second string
+	}
+}
diff --git a/spec/gopher_struct_tags_spec.lua b/spec/gopher_struct_tags_spec.lua
new file mode 100644
index 0000000..826933b
--- /dev/null
+++ b/spec/gopher_struct_tags_spec.lua
@@ -0,0 +1,56 @@
+local cur_dir = vim.fn.expand "%:p:h"
+
+describe("gopher.struct_tags", function()
+  it("can be required", function()
+    require "gopher.struct_tags"
+  end)
+
+  it("can add json tag to struct", function()
+    local add = require("gopher.struct_tags").add
+    local name = vim.fn.tempname() .. ".go"
+    local input_file = vim.fn.readfile(cur_dir .. "/spec/fixtures/tags/add_input.go")
+    local output_file = vim.fn.join(
+      vim.fn.readfile(cur_dir .. "/spec/fixtures/tags/add_output.go"),
+      "\n"
+    )
+
+    vim.fn.writefile(input_file, name)
+    vim.cmd("silent exe 'e " .. name .. "'")
+
+    local bufn = vim.fn.bufnr ""
+    vim.bo.filetype = "go"
+    vim.fn.setpos(".", { bufn, 3, 6, 0 })
+    add()
+
+    vim.wait(100, function() end)
+    local fmt = vim.fn.join(vim.fn.readfile(name), "\n")
+    assert.are.same(output_file, fmt)
+
+    vim.cmd("bd! " .. name)
+  end)
+
+  it("can remove json tag from struct", function()
+    local remove = require("gopher.struct_tags").remove
+    local name = vim.fn.tempname() .. ".go"
+    local input_file = vim.fn.readfile(cur_dir .. "/spec/fixtures/tags/remove_input.go")
+    local output_file = vim.fn.join(
+      vim.fn.readfile(cur_dir .. "/spec/fixtures/tags/remove_output.go"),
+      "\n"
+    )
+
+    vim.fn.writefile(input_file, name)
+    vim.cmd("silent exe 'e " .. name .. "'")
+
+    local bufn = vim.fn.bufnr ""
+    vim.bo.filetype = "go"
+    vim.fn.setpos(".", { bufn, 3, 6, 0 })
+    remove()
+
+    vim.wait(100, function() end)
+
+    local fmt = vim.fn.join(vim.fn.readfile(name), "\n")
+    assert.are.same(output_file, fmt)
+
+    vim.cmd("bd! " .. name)
+  end)
+end)