lsp: make the command error message more detailed (#11633)

* lsp.lua: make the error message more detailed

* test: add lsp._cmd_part test

1 files changed, 17 insertions, 1 deletions

diff --git a/test/functional/plugin/lsp_spec.lua b/test/functional/plugin/lsp_spec.lua
index f41a5323a8..e39511d0ea 100644
--- a/test/functional/plugin/lsp_spec.lua
+++ b/test/functional/plugin/lsp_spec.lua
@@ -6,6 +6,7 @@ local buf_lines = helpers.buf_lines
 local dedent = helpers.dedent
 local exec_lua = helpers.exec_lua
 local eq = helpers.eq
+local pcall_err = helpers.pcall_err
 local pesc = helpers.pesc
 local insert = helpers.insert
 local retry = helpers.retry
@@ -705,7 +706,6 @@ describe('LSP', function()
         end;
       }
     end)
-
   end)
 
   describe("parsing tests", function()
@@ -733,7 +733,23 @@ describe('LSP', function()
         end;
       }
     end)
+  end)
+  describe('lsp._cmd_parts test', function()
+    local function _cmd_parts(input)
+      return exec_lua([[
+        lsp = require('vim.lsp')
+        return lsp._cmd_parts(...)
+      ]], input)
+    end
+    it('should valid cmd argument', function()
+      eq(true, pcall(_cmd_parts, {"nvim"}))
+      eq(true, pcall(_cmd_parts, {"nvim", "--head"}))
+    end)
 
+    it('should invalid cmd argument', function()
+      eq('Error executing lua: .../shared.lua: cmd: expected list, got nvim', pcall_err(_cmd_parts, "nvim"))
+      eq('Error executing lua: .../shared.lua: cmd argument: expected string, got number', pcall_err(_cmd_parts, {"nvim", 1}))
+    end)
   end)
 end)