test/fs: sanity check for literal "~" directory (#6579)

If the CWD contains a directory with the literal name "~" then the tests
will have bogus failures.

3 files changed, 73 insertions, 64 deletions

diff --git a/src/nvim/os/fs.c b/src/nvim/os/fs.c
index c39ff5d358..aaa750db50 100644
--- a/src/nvim/os/fs.c
+++ b/src/nvim/os/fs.c
@@ -61,9 +61,9 @@ void fs_init(void)
 }
 
 
-/// Change to the given directory.
+/// Changes the current directory to `path`.
 ///
-/// @return `0` on success, a libuv error code on failure.
+/// @return 0 on success, or negative error code.
 int os_chdir(const char *path)
   FUNC_ATTR_NONNULL_ALL
 {
diff --git a/test/unit/os/fs_spec.lua b/test/unit/os/fs_spec.lua
index 860ebfdbcb..23eb05b4b8 100644
--- a/test/unit/os/fs_spec.lua
+++ b/test/unit/os/fs_spec.lua
@@ -35,7 +35,6 @@ for i = 0, 255 do
 end
 local fcontents = s:rep(16)
 
-local buffer = ""
 local directory = nil
 local absolute_executable = nil
 local executable_name = nil
@@ -65,7 +64,11 @@ local function os_getperm(filename)
   return tonumber(perm)
 end
 
-describe('fs function', function()
+describe('fs.c', function()
+  local function os_isdir(name)
+    return fs.os_isdir(to_cstr(name))
+  end
+
   before_each(function()
     lfs.mkdir('unit-test-directory');
 
@@ -91,32 +94,37 @@ describe('fs function', function()
   end)
 
   describe('os_dirname', function()
-    local length
-
-    local function os_dirname(buf, len)
-      return fs.os_dirname(buf, len)
-    end
-
-    before_each(function()
-      length = (string.len(lfs.currentdir())) + 1
-      buffer = cstr(length, '')
+    itp('returns OK and writes current directory to the buffer', function()
+      local length = string.len(lfs.currentdir()) + 1
+      local buf = cstr(length, '')
+      eq(OK, fs.os_dirname(buf, length))
+      eq(lfs.currentdir(), ffi.string(buf))
     end)
 
-    itp('returns OK and writes current directory into the buffer if it is large\n    enough', function()
-      eq(OK, (os_dirname(buffer, length)))
-      eq(lfs.currentdir(), (ffi.string(buffer)))
-    end)
-
-    -- What kind of other failing cases are possible?
     itp('returns FAIL if the buffer is too small', function()
-      local buf = cstr((length - 1), '')
-      eq(FAIL, (os_dirname(buf, (length - 1))))
+      local length = string.len(lfs.currentdir()) + 1
+      local buf = cstr(length - 1, '')
+      eq(FAIL, fs.os_dirname(buf, length - 1))
     end)
   end)
 
-  local function os_isdir(name)
-    return fs.os_isdir((to_cstr(name)))
-  end
+  describe('os_chdir', function()
+    itp('fails with path="~"', function()
+      eq(false, os_isdir('~')) -- sanity check: no literal "~" directory.
+      local length = 4096
+      local expected_cwd = cstr(length, '')
+      local cwd = cstr(length, '')
+      eq(OK, fs.os_dirname(expected_cwd, length))
+
+      -- os_chdir returns 0 for success, not OK (1).
+      neq(0, fs.os_chdir('~'))    -- fail
+      neq(0, fs.os_chdir('~/'))   -- fail
+
+      eq(OK, fs.os_dirname(cwd, length))
+      -- CWD did not change.
+      eq(ffi.string(expected_cwd), ffi.string(cwd))
+    end)
+  end)
 
   describe('os_isdir', function()
     itp('returns false if an empty string is given', function()
diff --git a/test/unit/path_spec.lua b/test/unit/path_spec.lua
index 470f971e68..6b9e2c8695 100644
--- a/test/unit/path_spec.lua
+++ b/test/unit/path_spec.lua
@@ -13,7 +13,7 @@ local OK = helpers.OK
 local FAIL = helpers.FAIL
 
 cimport('string.h')
-local path = cimport('./src/nvim/path.h')
+local cimp = cimport('./src/nvim/os/os.h', './src/nvim/path.h')
 
 local length = 0
 local buffer = nil
@@ -30,7 +30,7 @@ describe('path function', function()
 
     local function path_full_dir_name(directory, buf, len)
       directory = to_cstr(directory)
-      return path.path_full_dir_name(directory, buf, len)
+      return cimp.path_full_dir_name(directory, buf, len)
     end
 
     before_each(function()
@@ -69,7 +69,7 @@ describe('path function', function()
     local function path_full_compare(s1, s2, cn)
       s1 = to_cstr(s1)
       s2 = to_cstr(s2)
-      return path.path_full_compare(s1, s2, cn or 0)
+      return cimp.path_full_compare(s1, s2, cn or 0)
     end
 
     local f1 = 'f1.o'
@@ -86,31 +86,31 @@ describe('path function', function()
     end)
 
     itp('returns kEqualFiles when passed the same file', function()
-      eq(path.kEqualFiles, (path_full_compare(f1, f1)))
+      eq(cimp.kEqualFiles, (path_full_compare(f1, f1)))
     end)
 
     itp('returns kEqualFileNames when files that dont exist and have same name', function()
-      eq(path.kEqualFileNames, (path_full_compare('null.txt', 'null.txt', true)))
+      eq(cimp.kEqualFileNames, (path_full_compare('null.txt', 'null.txt', true)))
     end)
 
     itp('returns kBothFilesMissing when files that dont exist', function()
-      eq(path.kBothFilesMissing, (path_full_compare('null.txt', 'null.txt')))
+      eq(cimp.kBothFilesMissing, (path_full_compare('null.txt', 'null.txt')))
     end)
 
     itp('returns kDifferentFiles when passed different files', function()
-      eq(path.kDifferentFiles, (path_full_compare(f1, f2)))
-      eq(path.kDifferentFiles, (path_full_compare(f2, f1)))
+      eq(cimp.kDifferentFiles, (path_full_compare(f1, f2)))
+      eq(cimp.kDifferentFiles, (path_full_compare(f2, f1)))
     end)
 
     itp('returns kOneFileMissing if only one does not exist', function()
-      eq(path.kOneFileMissing, (path_full_compare(f1, 'null.txt')))
-      eq(path.kOneFileMissing, (path_full_compare('null.txt', f1)))
+      eq(cimp.kOneFileMissing, (path_full_compare(f1, 'null.txt')))
+      eq(cimp.kOneFileMissing, (path_full_compare('null.txt', f1)))
     end)
   end)
 
   describe('path_tail', function()
     local function path_tail(file)
-      local res = path.path_tail((to_cstr(file)))
+      local res = cimp.path_tail((to_cstr(file)))
       neq(NULL, res)
       return ffi.string(res)
     end
@@ -126,7 +126,7 @@ describe('path function', function()
 
   describe('path_tail_with_sep', function()
     local function path_tail_with_sep(file)
-      local res = path.path_tail_with_sep((to_cstr(file)))
+      local res = cimp.path_tail_with_sep((to_cstr(file)))
       neq(NULL, res)
       return ffi.string(res)
     end
@@ -159,11 +159,11 @@ describe('path function', function()
     -- strcmp.
     local function invocation_path_tail(invk)
       local plen = ffi.new('size_t[?]', 1)
-      local ptail = path.invocation_path_tail((to_cstr(invk)), plen)
+      local ptail = cimp.invocation_path_tail((to_cstr(invk)), plen)
       neq(NULL, ptail)
 
       -- it does not change the output if len==NULL
-      local tail2 = path.invocation_path_tail((to_cstr(invk)), NULL)
+      local tail2 = cimp.invocation_path_tail((to_cstr(invk)), NULL)
       neq(NULL, tail2)
       eq((ffi.string(ptail)), (ffi.string(tail2)))
       return ptail, plen[0]
@@ -204,7 +204,7 @@ describe('path function', function()
     end)
 
     itp('is equivalent to path_tail when args do not contain a path separator', function()
-      local ptail = path.path_tail(to_cstr("a/b/c x y z"))
+      local ptail = cimp.path_tail(to_cstr("a/b/c x y z"))
       neq(NULL, ptail)
       local tail = ffi.string(ptail)
       local invk, _ = invocation_path_tail("a/b/c x y z")
@@ -212,7 +212,7 @@ describe('path function', function()
     end)
 
     itp('is not equivalent to path_tail when args contain a path separator', function()
-      local ptail = path.path_tail(to_cstr("a/b/c x y/z"))
+      local ptail = cimp.path_tail(to_cstr("a/b/c x y/z"))
       neq(NULL, ptail)
       local invk, _ = invocation_path_tail("a/b/c x y/z")
       neq((ffi.string(ptail)), (ffi.string(invk)))
@@ -221,7 +221,7 @@ describe('path function', function()
 
   describe('path_next_component', function()
     local function path_next_component(file)
-      local res = path.path_next_component((to_cstr(file)))
+      local res = cimp.path_next_component((to_cstr(file)))
       neq(NULL, res)
       return ffi.string(res)
     end
@@ -238,25 +238,25 @@ describe('path function', function()
   describe('path_shorten_fname', function()
     itp('returns NULL if `full_path` is NULL', function()
       local dir = to_cstr('some/directory/file.txt')
-      eq(NULL, (path.path_shorten_fname(NULL, dir)))
+      eq(NULL, (cimp.path_shorten_fname(NULL, dir)))
     end)
 
     itp('returns NULL if the path and dir does not match', function()
       local dir = to_cstr('not/the/same')
       local full = to_cstr('as/this.txt')
-      eq(NULL, (path.path_shorten_fname(full, dir)))
+      eq(NULL, (cimp.path_shorten_fname(full, dir)))
     end)
 
     itp('returns NULL if the path is not separated properly', function()
       local dir = to_cstr('some/very/long/')
       local full = to_cstr('some/very/long/directory/file.txt')
-      eq(NULL, (path.path_shorten_fname(full, dir)))
+      eq(NULL, (cimp.path_shorten_fname(full, dir)))
     end)
 
     itp('shortens the filename if `dir_name` is the start of `full_path`', function()
       local full = to_cstr('some/very/long/directory/file.txt')
       local dir = to_cstr('some/very/long')
-      eq('directory/file.txt', (ffi.string(path.path_shorten_fname(full, dir))))
+      eq('directory/file.txt', (ffi.string(cimp.path_shorten_fname(full, dir))))
     end)
   end)
 end)
@@ -277,23 +277,23 @@ describe('path_shorten_fname_if_possible', function()
     itp('returns shortened path if possible', function()
       lfs.chdir('ut_directory')
       local full = to_cstr(lfs.currentdir() .. '/subdir/file.txt')
-      eq('subdir/file.txt', (ffi.string(path.path_shorten_fname_if_possible(full))))
+      eq('subdir/file.txt', (ffi.string(cimp.path_shorten_fname_if_possible(full))))
     end)
 
     itp('returns `full_path` if a shorter version is not possible', function()
       local old = lfs.currentdir()
       lfs.chdir('ut_directory')
       local full = old .. '/subdir/file.txt'
-      eq(full, (ffi.string(path.path_shorten_fname_if_possible(to_cstr(full)))))
+      eq(full, (ffi.string(cimp.path_shorten_fname_if_possible(to_cstr(full)))))
     end)
 
     itp('returns NULL if `full_path` is NULL', function()
-      eq(NULL, (path.path_shorten_fname_if_possible(NULL)))
+      eq(NULL, (cimp.path_shorten_fname_if_possible(NULL)))
     end)
   end)
 end)
 
-describe('more path function', function()
+describe('path.c', function()
   setup(function()
     lfs.mkdir('unit-test-directory');
     io.open('unit-test-directory/test.file', 'w').close()
@@ -315,7 +315,7 @@ describe('more path function', function()
   describe('vim_FullName', function()
     local function vim_FullName(filename, buf, len, force)
       filename = to_cstr(filename)
-      return path.vim_FullName(filename, buf, len, force)
+      return cimp.vim_FullName(filename, buf, len, force)
     end
 
     before_each(function()
@@ -326,7 +326,7 @@ describe('more path function', function()
 
     itp('fails if given filename is NULL', function()
       local force_expansion = 1
-      local result = path.vim_FullName(NULL, buffer, length, force_expansion)
+      local result = cimp.vim_FullName(NULL, buffer, length, force_expansion)
       eq(FAIL, result)
     end)
 
@@ -335,7 +335,7 @@ describe('more path function', function()
       local filename = 'foo/bar/bazzzzzzz/buz/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/a'
       local too_short_len = 8
       local buf = cstr(too_short_len, '')
-      local result = path.vim_FullName(filename, buf, too_short_len, force_expansion)
+      local result = cimp.vim_FullName(filename, buf, too_short_len, force_expansion)
       local expected = string.sub(filename, 1, (too_short_len - 1))
       eq(expected, (ffi.string(buf)))
       eq(FAIL, result)
@@ -357,7 +357,7 @@ describe('more path function', function()
       eq(FAIL, result)
     end)
 
-    itp('concatenates given filename if it does not contain a slash', function()
+    itp('concatenates filename if it does not contain a slash', function()
       local force_expansion = 1
       local result = vim_FullName('test.file', buffer, length, force_expansion)
       local expected = lfs.currentdir() .. '/test.file'
@@ -365,7 +365,7 @@ describe('more path function', function()
       eq(OK, result)
     end)
 
-    itp('concatenates given filename if it is a directory but does not contain a\n    slash', function()
+    itp('concatenates directory name if it does not contain a slash', function()
       local force_expansion = 1
       local result = vim_FullName('..', buffer, length, force_expansion)
       local expected = lfs.currentdir() .. '/..'
@@ -395,6 +395,7 @@ describe('more path function', function()
     end)
 
     itp('fails and uses filename when the path is relative to HOME', function()
+      eq(false, cimp.os_isdir('~')) -- sanity check: no literal "~" directory.
       local force_expansion = 1
       local absolute_path = '~/home.file'
       local result = vim_FullName(absolute_path, buffer, length, force_expansion)
@@ -414,7 +415,7 @@ describe('more path function', function()
       local filename = to_cstr('unit-test-directory/test.file')
       -- Don't use the wrapper here but pass a cstring directly to the c
       -- function.
-      local result = path.vim_FullName(filename, buffer, length, force_expansion)
+      local result = cimp.vim_FullName(filename, buffer, length, force_expansion)
       eq(lfs.currentdir() .. '/unit-test-directory/test.file', (ffi.string(buffer)))
       eq('unit-test-directory/test.file', (ffi.string(filename)))
       eq(OK, result)
@@ -423,7 +424,7 @@ describe('more path function', function()
     itp('works with directories that have one path component', function()
       local force_expansion = 1
       local filename = to_cstr('/tmp')
-      local result = path.vim_FullName(filename, buffer, length, force_expansion)
+      local result = cimp.vim_FullName(filename, buffer, length, force_expansion)
       eq('/tmp', ffi.string(buffer))
       eq(OK, result)
     end)
@@ -432,7 +433,7 @@ describe('more path function', function()
   describe('path_fix_case', function()
     local function fix_case(file)
       local c_file = to_cstr(file)
-      path.path_fix_case(c_file)
+      cimp.path_fix_case(c_file)
       return ffi.string(c_file)
     end
 
@@ -456,41 +457,41 @@ describe('more path function', function()
     itp('joins given paths with a slash', function()
       local path1 = cstr(100, 'path1')
       local to_append = to_cstr('path2')
-      eq(OK, (path.append_path(path1, to_append, 100)))
+      eq(OK, (cimp.append_path(path1, to_append, 100)))
       eq("path1/path2", (ffi.string(path1)))
     end)
 
     itp('joins given paths without adding an unnecessary slash', function()
       local path1 = cstr(100, 'path1/')
       local to_append = to_cstr('path2')
-      eq(OK, path.append_path(path1, to_append, 100))
+      eq(OK, cimp.append_path(path1, to_append, 100))
       eq("path1/path2", (ffi.string(path1)))
     end)
 
     itp('fails and uses filename if there is not enough space left for to_append', function()
       local path1 = cstr(11, 'path1/')
       local to_append = to_cstr('path2')
-      eq(FAIL, (path.append_path(path1, to_append, 11)))
+      eq(FAIL, (cimp.append_path(path1, to_append, 11)))
     end)
 
     itp('does not append a slash if to_append is empty', function()
       local path1 = cstr(6, 'path1')
       local to_append = to_cstr('')
-      eq(OK, (path.append_path(path1, to_append, 6)))
+      eq(OK, (cimp.append_path(path1, to_append, 6)))
       eq('path1', (ffi.string(path1)))
     end)
 
     itp('does not append unnecessary dots', function()
       local path1 = cstr(6, 'path1')
       local to_append = to_cstr('.')
-      eq(OK, (path.append_path(path1, to_append, 6)))
+      eq(OK, (cimp.append_path(path1, to_append, 6)))
       eq('path1', (ffi.string(path1)))
     end)
 
     itp('copies to_append to path, if path is empty', function()
       local path1 = cstr(7, '')
       local to_append = to_cstr('/path2')
-      eq(OK, (path.append_path(path1, to_append, 7)))
+      eq(OK, (cimp.append_path(path1, to_append, 7)))
       eq('/path2', (ffi.string(path1)))
     end)
   end)
@@ -498,7 +499,7 @@ describe('more path function', function()
   describe('path_is_absolute_path', function()
     local function path_is_absolute_path(filename)
       filename = to_cstr(filename)
-      return path.path_is_absolute_path(filename)
+      return cimp.path_is_absolute_path(filename)
     end
 
     itp('returns true if filename starts with a slash', function()