2 files changed, 55 insertions, 2 deletions
diff --git a/test/unit/os/env_spec.lua b/test/unit/os/env_spec.lua
index 575787a25e..cefd0315b7 100644
--- a/test/unit/os/env_spec.lua
+++ b/test/unit/os/env_spec.lua
@@ -13,7 +13,7 @@ require('lfs')
 
 local cimp = cimport('./src/nvim/os/os.h')
 
-describe('env function', function()
+describe('env.c', function()
   local function os_setenv(name, value, override)
     return cimp.os_setenv(to_cstr(name), to_cstr(value), override)
   end
diff --git a/test/unit/path_spec.lua b/test/unit/path_spec.lua
index 6b9e2c8695..a9cba7df84 100644
--- a/test/unit/path_spec.lua
+++ b/test/unit/path_spec.lua
@@ -18,7 +18,7 @@ local cimp = cimport('./src/nvim/os/os.h', './src/nvim/path.h')
 local length = 0
 local buffer = nil
 
-describe('path function', function()
+describe('path.c', function()
   describe('path_full_dir_name', function()
     setup(function()
       lfs.mkdir('unit-test-directory')
@@ -293,6 +293,59 @@ describe('path_shorten_fname_if_possible', function()
   end)
 end)
 
+describe('path.c path_guess_exepath', function()
+  local cwd = lfs.currentdir()
+
+  for _,name in ipairs({'./nvim', '.nvim', 'foo/nvim'}) do
+    itp('"'..name..'" returns name catenated with CWD', function()
+      local bufsize = 255
+      local buf = cstr(bufsize, '')
+      cimp.path_guess_exepath(name, buf, bufsize)
+      eq(cwd..'/'..name, ffi.string(buf))
+    end)
+  end
+
+  itp('absolute path returns the name unmodified', function()
+    local name = '/foo/bar/baz'
+    local bufsize = 255
+    local buf = cstr(bufsize, '')
+    cimp.path_guess_exepath(name, buf, bufsize)
+    eq(name, ffi.string(buf))
+  end)
+
+  itp('returns the name unmodified if not found in $PATH', function()
+    local name = '23u0293_not_in_path'
+    local bufsize = 255
+    local buf = cstr(bufsize, '')
+    cimp.path_guess_exepath(name, buf, bufsize)
+    eq(name, ffi.string(buf))
+  end)
+
+  itp('does not crash if $PATH item exceeds MAXPATHL', function()
+    local orig_path_env = os.getenv('PATH')
+    local name = 'cat'  -- Some executable in $PATH.
+    local bufsize = 255
+    local buf = cstr(bufsize, '')
+    local insane_path = orig_path_env..':'..(("x/"):rep(4097))
+
+    cimp.os_setenv('PATH', insane_path, true)
+    cimp.path_guess_exepath(name, buf, bufsize)
+    eq('bin/' .. name, ffi.string(buf):sub(-#('bin/' .. name), -1))
+
+    -- Restore $PATH.
+    cimp.os_setenv('PATH', orig_path_env, true)
+  end)
+
+  itp('returns full path found in $PATH', function()
+    local name = 'cat'  -- Some executable in $PATH.
+    local bufsize = 255
+    local buf = cstr(bufsize, '')
+    cimp.path_guess_exepath(name, buf, bufsize)
+    -- Usually "/bin/cat" on unix, "/path/to/nvim/cat" on Windows.
+    eq('bin/' .. name, ffi.string(buf):sub(-#('bin/' .. name), -1))
+  end)
+end)
+
 describe('path.c', function()
   setup(function()
     lfs.mkdir('unit-test-directory');