diff --git a/spec/async_integration_spec.lua b/spec/async_integration_spec.lua
index 7a90ce1..dd4c523 100644
--- a/spec/async_integration_spec.lua
+++ b/spec/async_integration_spec.lua
@@ -75,10 +75,15 @@ describe('async integration', function()
       end,
     }
 
-    vim.cmd = {
+    local cmd_methods = {
       e = function() end,
       only = function() end,
+      startinsert = function() end,
+      stopinsert = function() end,
     }
+    vim.cmd = setmetatable(function() end, {
+      __index = cmd_methods,
+    })
     vim.api.nvim_get_current_buf = function()
       return 1
     end
diff --git a/spec/async_setup_spec.lua b/spec/async_setup_spec.lua
index 2f2fd83..f6b9904 100644
--- a/spec/async_setup_spec.lua
+++ b/spec/async_setup_spec.lua
@@ -20,7 +20,7 @@ describe('cp.async.setup', function()
           },
         })
       end,
-      scrape_problem_async = function(platform, contest_id, problem_id, callback)
+      scrape_problem_async = function(_, _, problem_id, callback)
         callback({
           success = true,
           problem_id = problem_id,
@@ -69,10 +69,15 @@ describe('cp.async.setup', function()
       end,
     }
 
-    vim.cmd = {
+    local cmd_methods = {
       e = function() end,
       only = function() end,
+      startinsert = function() end,
+      stopinsert = function() end,
     }
+    vim.cmd = setmetatable(function() end, {
+      __index = cmd_methods,
+    })
     vim.api.nvim_get_current_buf = function()
       return 1
     end
diff --git a/spec/cache_spec.lua b/spec/cache_spec.lua
index a72946a..2f5053a 100644
--- a/spec/cache_spec.lua
+++ b/spec/cache_spec.lua
@@ -4,6 +4,19 @@ describe('cp.cache', function()
 
   before_each(function()
     spec_helper.setup()
+
+    local mock_file_content = '{}'
+    vim.fn.filereadable = function()
+      return 1
+    end
+    vim.fn.readfile = function()
+      return { mock_file_content }
+    end
+    vim.fn.writefile = function(lines)
+      mock_file_content = table.concat(lines, '\n')
+    end
+    vim.fn.mkdir = function() end
+
     cache = require('cp.cache')
     cache.load()
   end)
diff --git a/spec/command_parsing_spec.lua b/spec/command_parsing_spec.lua
index 693f2b2..f37eb15 100644
--- a/spec/command_parsing_spec.lua
+++ b/spec/command_parsing_spec.lua
@@ -12,6 +12,29 @@ describe('cp command parsing', function()
     }
     package.loaded['cp.log'] = mock_logger
 
+    local mock_async_setup = {
+      setup_contest_async = function() end,
+      handle_full_setup_async = function() end,
+      setup_problem_async = function() end,
+    }
+    package.loaded['cp.async.setup'] = mock_async_setup
+    local mock_setup = {
+      set_platform = function()
+        return true
+      end,
+    }
+    package.loaded['cp.setup'] = mock_setup
+
+    local mock_state = {
+      get_platform = function()
+        return 'atcoder'
+      end,
+      get_contest_id = function()
+        return 'abc123'
+      end,
+    }
+    package.loaded['cp.state'] = mock_state
+
     cp = require('cp')
     cp.setup({
       contests = {
@@ -29,6 +52,9 @@ describe('cp command parsing', function()
 
   after_each(function()
     package.loaded['cp.log'] = nil
+    package.loaded['cp.async.setup'] = nil
+    package.loaded['cp.setup'] = nil
+    package.loaded['cp.state'] = nil
   end)
 
   describe('empty arguments', function()