refactor(vim.version): cleanup

- version.cmp(): assert valid version
- add test for loading vim.version (the other tests use shared.lua in
  the test runner)
- reduce test scopes, reword test descriptions

6 files changed, 423 insertions, 462 deletions

diff --git a/runtime/doc/lua.txt b/runtime/doc/lua.txt
index 3c48cd37a6..697cd86e8a 100644
--- a/runtime/doc/lua.txt
+++ b/runtime/doc/lua.txt
@@ -2501,12 +2501,12 @@ trust({opts})                                             *vim.secure.trust()*
 ==============================================================================
 Lua module: version                                              *lua-version*
 
-cmp({v1}, {v2}, {opts})                                        *version.cmp()*
+cmp({v1}, {v2}, {opts})                                    *vim.version.cmp()*
     Compares two strings ( `v1` and `v2` ) in semver format.
 
     Parameters: ~
       • {v1}    (string) Version.
-      • {v2}    (string) Version to be compared with v1.
+      • {v2}    (string) Version to compare with v1.
       • {opts}  (table|nil) Optional keyword arguments:
                 • strict (boolean): see `semver.parse` for details. Defaults
                   to false.
@@ -2514,59 +2514,54 @@ cmp({v1}, {v2}, {opts})                                        *version.cmp()*
     Return: ~
         (integer) `-1` if `v1 < v2`, `0` if `v1 == v2`, `1` if `v1 > v2`.
 
-eq({version_1}, {version_2})                                    *version.eq()*
+eq({v1}, {v2})                                              *vim.version.eq()*
     Returns `true` if `v1` are `v2` are equal versions.
 
     Parameters: ~
-      • {version_1}  (string)
-      • {version_2}  (string)
+      • {v1}  (string)
+      • {v2}  (string)
 
     Return: ~
         (boolean)
 
-gt({version_1}, {version_2})                                    *version.gt()*
+gt({v1}, {v2})                                              *vim.version.gt()*
     Returns `true` if `v1` is greater than `v2` .
 
     Parameters: ~
-      • {version_1}  (string)
-      • {version_2}  (string)
+      • {v1}  (string)
+      • {v2}  (string)
 
     Return: ~
         (boolean)
 
-lt({version_1}, {version_2})                                    *version.lt()*
+lt({v1}, {v2})                                              *vim.version.lt()*
     Returns `true` if `v1` is less than `v2` .
 
     Parameters: ~
-      • {version_1}  (string)
-      • {version_2}  (string)
+      • {v1}  (string)
+      • {v2}  (string)
 
     Return: ~
         (boolean)
 
-parse({version}, {opts})                                     *version.parse()*
-    Parses a semantically formatted version string into a table.
+parse({version}, {opts})                                 *vim.version.parse()*
+    Parses a semantic version string.
 
-    Supports leading "v" and leading and trailing whitespace in the version
-    string. e.g. `" v1.0.1-rc1+build.2"` , `"1.0.1-rc1+build.2"`,
-    `"v1.0.1-rc1+build.2"` and `"v1.0.1-rc1+build.2 "` will be parsed as:
+    Ignores leading "v" and surrounding whitespace, e.g. "
+    v1.0.1-rc1+build.2", "1.0.1-rc1+build.2", "v1.0.1-rc1+build.2" and
+    "v1.0.1-rc1+build.2 " are all parsed as: >
 
-    { major = 1, minor = 0, patch = 1, prerelease = 'rc1 , build = 'build.2' }`
+       { major = 1, minor = 0, patch = 1, prerelease = "rc1", build = "build.2" }
+<
 
     Parameters: ~
       • {version}  (string) Version string to be parsed.
       • {opts}     (table|nil) Optional keyword arguments:
-                   • strict (boolean): when set to `true` an error will be
-                     thrown for version strings that do not conform to the
-                     semver specification (v2.0.0) (see
-                     semver.org/spec/v2.0.0.html for details). This means that
-                     `semver.parse('v1.2)` will throw an error. When set to
-                     `false`, `semver.parse('v1.2)` will coerce 'v1.2' to
-                     'v1.2.0' and return the table: `{ major = 1, minor = 2,
-                     patch = 0 }`. Defaults to false.
+                   • strict (boolean): Default false. If `true` , no coercion is attempted on input not strictly
+                     conforming to semver v2.0.0 ( https://semver.org/spec/v2.0.0.html ). E.g. `parse("v1.2")` returns nil.
 
     Return: ~
         (table|nil) parsed_version Parsed version table or `nil` if `version`
-        is not valid.
+        is invalid.
 
  vim:tw=78:ts=8:sw=4:sts=4:et:ft=help:norl:
diff --git a/runtime/doc/news.txt b/runtime/doc/news.txt
index b5cb975066..28fdaa770d 100644
--- a/runtime/doc/news.txt
+++ b/runtime/doc/news.txt
@@ -55,9 +55,8 @@ NEW FEATURES                                                    *news-features*
 
 The following new APIs or features were added.
 
-• Added |version.parse()|, |version.cmp()|, |version.lt()|, |version.eq()|
-  and |version.gt()| to |vim.version| for parsing and comparing version numbers
-  according to the semver specification, see |lua-version|.
+• Added |vim.version| for parsing and comparing version strings conforming to
+  the semver specification, see |lua-version|.
 
 • A new environment variable named NVIM_APPNAME enables configuring the
   directories where Neovim should find its configuration and state files. See
diff --git a/runtime/lua/vim/_init_packages.lua b/runtime/lua/vim/_init_packages.lua
index d032026796..57c0fc9122 100644
--- a/runtime/lua/vim/_init_packages.lua
+++ b/runtime/lua/vim/_init_packages.lua
@@ -51,7 +51,10 @@ end
 -- builtin functions which always should be available
 require('vim.shared')
 
-vim._submodules = { inspect = true }
+vim._submodules = {
+  inspect = true,
+  version = true,
+}
 
 -- These are for loading runtime modules in the vim namespace lazily.
 setmetatable(vim, {
@@ -69,9 +72,6 @@ setmetatable(vim, {
         t[key] = val
         return t[key]
       end
-    elseif key == 'version' then
-      t[key] = require('vim.version')
-      return t[key]
     end
   end,
 })
diff --git a/runtime/lua/vim/version.lua b/runtime/lua/vim/version.lua
index 49ef019295..ddbe228244 100644
--- a/runtime/lua/vim/version.lua
+++ b/runtime/lua/vim/version.lua
@@ -1,23 +1,41 @@
 local M = {}
 
 ---@private
+---@param version string
+---@return string
+local function create_err_msg(version)
+  return string.format('invalid version: "%s"', version)
+end
+
+---@private
+--- Throws an error if `version` cannot be parsed.
+---@param version string
+local function assert_version(version, opt)
+  local rv = M.parse(version, opt)
+  if rv == nil then
+    error(create_err_msg(version))
+  end
+  return rv
+end
+
+---@private
 --- Compares the prerelease component of the two versions.
----@param v1_parsed table Parsed version.
----@param v2_parsed table Parsed version.
----@return integer `-1` if `v1_parsed < v2_parsed`, `0` if `v1_parsed == v2_parsed`, `1` if `v1_parsed > v2_parsed`.
-local function cmp_prerelease(v1_parsed, v2_parsed)
-  if v1_parsed.prerelease and not v2_parsed.prerelease then
+---@param v1 table Parsed version.
+---@param v2 table Parsed version.
+---@return integer `-1` if `v1 < v2`, `0` if `v1 == v2`, `1` if `v1 > v2`.
+local function cmp_prerelease(v1, v2)
+  if v1.prerelease and not v2.prerelease then
     return -1
   end
-  if not v1_parsed.prerelease and v2_parsed.prerelease then
+  if not v1.prerelease and v2.prerelease then
     return 1
   end
-  if not v1_parsed.prerelease and not v2_parsed.prerelease then
+  if not v1.prerelease and not v2.prerelease then
     return 0
   end
 
-  local v1_identifiers = vim.split(v1_parsed.prerelease, '.', { plain = true })
-  local v2_identifiers = vim.split(v2_parsed.prerelease, '.', { plain = true })
+  local v1_identifiers = vim.split(v1.prerelease, '.', { plain = true })
+  local v2_identifiers = vim.split(v2.prerelease, '.', { plain = true })
   local i = 1
   local max = math.max(vim.tbl_count(v1_identifiers), vim.tbl_count(v2_identifiers))
   while i <= max do
@@ -71,23 +89,15 @@ end
 
 ---@private
 --- Compares the version core component of the two versions.
----@param v1_parsed table Parsed version.
----@param v2_parsed table Parsed version.
----@return integer `-1` if `v1_parsed < v2_parsed`, `0` if `v1_parsed == v2_parsed`, `1` if `v1_parsed > v2_parsed`.
-local function cmp_version_core(v1_parsed, v2_parsed)
-  if
-    v1_parsed.major == v2_parsed.major
-    and v1_parsed.minor == v2_parsed.minor
-    and v1_parsed.patch == v2_parsed.patch
-  then
+---@param v1 table Parsed version.
+---@param v2 table Parsed version.
+---@return integer `-1` if `v1 < v2`, `0` if `v1 == v2`, `1` if `v1 > v2`.
+local function cmp_version_core(v1, v2)
+  if v1.major == v2.major and v1.minor == v2.minor and v1.patch == v2.patch then
     return 0
   end
 
-  if
-    v1_parsed.major > v2_parsed.major
-    or v1_parsed.minor > v2_parsed.minor
-    or v1_parsed.patch > v2_parsed.patch
-  then
+  if v1.major > v2.major or v1.minor > v2.minor or v1.patch > v2.patch then
     return 1
   end
 
@@ -96,14 +106,14 @@ end
 
 --- Compares two strings (`v1` and `v2`) in semver format.
 ---@param v1 string Version.
----@param v2 string Version to be compared with v1.
+---@param v2 string Version to compare with v1.
 ---@param opts table|nil Optional keyword arguments:
 ---                      - strict (boolean):  see `semver.parse` for details. Defaults to false.
 ---@return integer `-1` if `v1 < v2`, `0` if `v1 == v2`, `1` if `v1 > v2`.
 function M.cmp(v1, v2, opts)
   opts = opts or { strict = false }
-  local v1_parsed = M.parse(v1, opts)
-  local v2_parsed = M.parse(v2, opts)
+  local v1_parsed = assert_version(v1, opts)
+  local v2_parsed = assert_version(v2, opts)
 
   local result = cmp_version_core(v1_parsed, v2_parsed)
   if result == 0 then
@@ -188,30 +198,20 @@ local function is_prerelease_and_build_valid(prerelease_and_build)
   return has_build or has_prerelease or has_prerelease_and_build
 end
 
----@private
----@param version string
----@return string
-local function create_err_msg(version)
-  return string.format('invalid version: "%s"', version)
-end
-
---- Parses a semantically formatted version string into a table.
----
---- Supports leading "v" and leading and trailing whitespace in the version
---- string. e.g. `" v1.0.1-rc1+build.2"` , `"1.0.1-rc1+build.2"`, `"v1.0.1-rc1+build.2"`
---- and `"v1.0.1-rc1+build.2 "` will be parsed as:
+--- Parses a semantic version string.
 ---
---- `{ major = 1, minor = 0, patch = 1, prerelease = 'rc1', build = 'build.2' }`
+--- Ignores leading "v" and surrounding whitespace, e.g. " v1.0.1-rc1+build.2",
+--- "1.0.1-rc1+build.2", "v1.0.1-rc1+build.2" and "v1.0.1-rc1+build.2 " are all parsed as:
+--- <pre>
+---   { major = 1, minor = 0, patch = 1, prerelease = "rc1", build = "build.2" }
+--- </pre>
 ---
 ---@param version string Version string to be parsed.
 ---@param opts table|nil Optional keyword arguments:
----                      - strict (boolean):  when set to `true` an error will be thrown for version
----                      strings that do not conform to the semver specification (v2.0.0) (see
----                      semver.org/spec/v2.0.0.html for details). This means that
----                      `semver.parse('v1.2)` will throw an error. When set to `false`,
----                      `semver.parse('v1.2)` will coerce 'v1.2' to 'v1.2.0' and return the table:
----                      `{ major = 1, minor = 2, patch = 0 }`. Defaults to false.
----@return table|nil parsed_version Parsed version table or `nil` if `version` is not valid.
+---                      - strict (boolean):  Default false. If `true`, no coercion is attempted on
+---                      input not strictly conforming to semver v2.0.0
+---                      (https://semver.org/spec/v2.0.0.html). E.g. `parse("v1.2")` returns nil.
+---@return table|nil parsed_version Parsed version table or `nil` if `version` is invalid.
 function M.parse(version, opts)
   if type(version) ~= 'string' then
     error(create_err_msg(version))
@@ -246,46 +246,28 @@ function M.parse(version, opts)
   }
 end
 
----@private
---- Throws an error if `version` cannot be parsed.
----@param version string
-local function assert_version(version)
-  if M.parse(version) == nil then
-    error(create_err_msg(version))
-  end
-end
-
 ---Returns `true` if `v1` are `v2` are equal versions.
----@param version_1 string
----@param version_2 string
+---@param v1 string
+---@param v2 string
 ---@return boolean
-function M.eq(version_1, version_2)
-  assert_version(version_1)
-  assert_version(version_2)
-
-  return M.cmp(version_1, version_2) == 0
+function M.eq(v1, v2)
+  return M.cmp(v1, v2) == 0
 end
 
 ---Returns `true` if `v1` is less than `v2`.
----@param version_1 string
----@param version_2 string
+---@param v1 string
+---@param v2 string
 ---@return boolean
-function M.lt(version_1, version_2)
-  assert_version(version_1)
-  assert_version(version_2)
-
-  return M.cmp(version_1, version_2) == -1
+function M.lt(v1, v2)
+  return M.cmp(v1, v2) == -1
 end
 
 ---Returns `true` if `v1` is greater than `v2`.
----@param version_1 string
----@param version_2 string
+---@param v1 string
+---@param v2 string
 ---@return boolean
-function M.gt(version_1, version_2)
-  assert_version(version_1)
-  assert_version(version_2)
-
-  return M.cmp(version_1, version_2) == 1
+function M.gt(v1, v2)
+  return M.cmp(v1, v2) == 1
 end
 
 setmetatable(M, {
diff --git a/scripts/gen_vimdoc.py b/scripts/gen_vimdoc.py
index 45a6d8e402..1e85fa49e9 100755
--- a/scripts/gen_vimdoc.py
+++ b/scripts/gen_vimdoc.py
@@ -194,6 +194,7 @@ CONFIG = {
             'keymap': 'vim.keymap',
             'fs': 'vim.fs',
             'secure': 'vim.secure',
+            'version': 'vim.version',
         },
         'append_only': [
             'shared.lua',
diff --git a/test/functional/lua/version_spec.lua b/test/functional/lua/version_spec.lua
index 23f3cec948..9e41330915 100644
--- a/test/functional/lua/version_spec.lua
+++ b/test/functional/lua/version_spec.lua
@@ -1,165 +1,176 @@
 local helpers = require('test.functional.helpers')(after_each)
+local clear = helpers.clear
 local eq = helpers.eq
-local pcall_err = helpers.pcall_err
+local exec_lua = helpers.exec_lua
 local matches = helpers.matches
+local pcall_err = helpers.pcall_err
 
 local version = require('vim.version')
 
+local function quote_empty(s)
+  return tostring(s) == '' and '""' or tostring(s)
+end
+
 describe('version', function()
+  it('package', function()
+    clear()
+    eq({ major = 42, minor = 3, patch = 99 }, exec_lua("return vim.version.parse('v42.3.99')"))
+  end)
+
   describe('cmp()', function()
     local testcases = {
       {
-        desc = 'v1 < v2',
+        desc = '(v1 < v2)',
         v1 = 'v0.0.0',
         v2 = 'v9.0.0',
         want = -1,
       },
       {
-        desc = 'v1 < v2',
+        desc = '(v1 < v2)',
         v1 = 'v0.0.0',
         v2 = 'v0.9.0',
         want = -1,
       },
       {
-        desc = 'v1 < v2',
+        desc = '(v1 < v2)',
         v1 = 'v0.0.0',
         v2 = 'v0.0.9',
         want = -1,
       },
       {
-        desc = 'v1 == v2',
+        desc = '(v1 == v2)',
         v1 = 'v0.0.0',
         v2 = 'v0.0.0',
         want = 0,
       },
       {
-        desc = 'v1 > v2',
+        desc = '(v1 > v2)',
         v1 = 'v9.0.0',
         v2 = 'v0.0.0',
         want = 1,
       },
       {
-        desc = 'v1 > v2',
+        desc = '(v1 > v2)',
         v1 = 'v0.9.0',
         v2 = 'v0.0.0',
         want = 1,
       },
       {
-        desc = 'v1 > v2',
+        desc = '(v1 > v2)',
         v1 = 'v0.0.9',
         v2 = 'v0.0.0',
         want = 1,
       },
       {
-        desc = 'v1 < v2 when v1 has prerelease',
+        desc = '(v1 < v2) when v1 has prerelease',
         v1 = 'v1.0.0-alpha',
         v2 = 'v1.0.0',
         want = -1,
       },
       {
-        desc = 'v1 > v2 when v2 has prerelease',
+        desc = '(v1 > v2) when v2 has prerelease',
         v1 = '1.0.0',
         v2 = '1.0.0-alpha',
         want = 1,
       },
       {
-        desc = 'v1 > v2 when v1 has a higher number identifier',
+        desc = '(v1 > v2) when v1 has a higher number identifier',
         v1 = '1.0.0-2',
         v2 = '1.0.0-1',
         want = 1,
       },
       {
-        desc = 'v1 < v2 when v2 has a higher number identifier',
+        desc = '(v1 < v2) when v2 has a higher number identifier',
         v1 = '1.0.0-2',
         v2 = '1.0.0-9',
         want = -1,
       },
       {
-        desc = 'v1 < v2 when v2 has more identifiers',
+        desc = '(v1 < v2) when v2 has more identifiers',
         v1 = '1.0.0-2',
         v2 = '1.0.0-2.0',
         want = -1,
       },
       {
-        desc = 'v1 > v2 when v1 has more identifiers',
+        desc = '(v1 > v2) when v1 has more identifiers',
         v1 = '1.0.0-2.0',
         v2 = '1.0.0-2',
         want = 1,
       },
       {
-        desc = 'v1 == v2 when v2 has same numeric identifiers',
+        desc = '(v1 == v2) when v2 has same numeric identifiers',
         v1 = '1.0.0-2.0',
         v2 = '1.0.0-2.0',
         want = 0,
       },
       {
-        desc = 'v1 == v2 when v2 has same alphabet identifiers',
+        desc = '(v1 == v2) when v2 has same alphabet identifiers',
         v1 = '1.0.0-alpha',
         v2 = '1.0.0-alpha',
         want = 0,
       },
       {
-        desc = 'v1 < v2 when v2 has an alphabet identifier with a higher ASCII sort order',
+        desc = '(v1 < v2) when v2 has an alphabet identifier with higher ASCII sort order',
         v1 = '1.0.0-alpha',
         v2 = '1.0.0-beta',
         want = -1,
       },
       {
-        desc = 'v1 > v2 when v1 has an alphabet identifier with a higher ASCII sort order',
+        desc = '(v1 > v2) when v1 has an alphabet identifier with higher ASCII sort order',
         v1 = '1.0.0-beta',
         v2 = '1.0.0-alpha',
         want = 1,
       },
       {
-        desc = 'v1 < v2 when v2 has prerelease and number identifer',
+        desc = '(v1 < v2) when v2 has prerelease and number identifer',
         v1 = '1.0.0-alpha',
         v2 = '1.0.0-alpha.1',
         want = -1,
       },
       {
-        desc = 'v1 > v2 when v1 has prerelease and number identifer',
+        desc = '(v1 > v2) when v1 has prerelease and number identifer',
         v1 = '1.0.0-alpha.1',
         v2 = '1.0.0-alpha',
         want = 1,
       },
       {
-        desc = 'v1 > v2 when v1 has an additional alphabet identifier',
+        desc = '(v1 > v2) when v1 has an additional alphabet identifier',
         v1 = '1.0.0-alpha.beta',
         v2 = '1.0.0-alpha',
         want = 1,
       },
       {
-        desc = 'v1 < v2 when v2 has an additional alphabet identifier',
+        desc = '(v1 < v2) when v2 has an additional alphabet identifier',
         v1 = '1.0.0-alpha',
         v2 = '1.0.0-alpha.beta',
         want = -1,
       },
       {
-        desc = 'v1 < v2 when v2 has an a first alphabet identifier with higher precedence',
+        desc = '(v1 < v2) when v2 has an a first alphabet identifier with higher precedence',
         v1 = '1.0.0-alpha.beta',
         v2 = '1.0.0-beta',
         want = -1,
       },
       {
-        desc = 'v1 > v2 when v1 has an a first alphabet identifier with higher precedence',
+        desc = '(v1 > v2) when v1 has an a first alphabet identifier with higher precedence',
         v1 = '1.0.0-beta',
         v2 = '1.0.0-alpha.beta',
         want = 1,
       },
       {
-        desc = 'v1 < v2 when v2 has an additional number identifer',
+        desc = '(v1 < v2) when v2 has an additional number identifer',
         v1 = '1.0.0-beta',
         v2 = '1.0.0-beta.2',
         want = -1,
       },
       {
-        desc = 'v1 < v2 when v2 has same first alphabet identifier but has a higher number identifer',
+        desc = '(v1 < v2) when v2 has same first alphabet identifier but has a higher number identifer',
         v1 = '1.0.0-beta.2',
         v2 = '1.0.0-beta.11',
         want = -1,
       },
       {
-        desc = 'v1 < v2 when v2 has higher alphabet precedence',
+        desc = '(v1 < v2) when v2 has higher alphabet precedence',
         v1 = '1.0.0-beta.11',
         v2 = '1.0.0-rc.1',
         want = -1,
@@ -167,7 +178,7 @@ describe('version', function()
     }
     for _, tc in ipairs(testcases) do
       it(
-        string.format('returns %d if %s (v1 = %s, v2 = %s)', tc.want, tc.desc, tc.v1, tc.v2),
+        string.format('%d %s (v1 = %s, v2 = %s)', tc.want, tc.desc, tc.v1, tc.v2),
         function()
           eq(tc.want, version.cmp(tc.v1, tc.v2, { strict = true }))
         end
@@ -176,410 +187,383 @@ describe('version', function()
   end)
 
   describe('parse()', function()
-    describe('parsing', function()
-      describe('strict = true', function()
-        local testcases = {
-          {
-            desc = 'a version without leading "v"',
-            version = '10.20.123',
-            want = {
-              major = 10,
-              minor = 20,
-              patch = 123,
-              prerelease = nil,
-              build = nil,
-            },
-          },
-          {
-            desc = 'a valid version with a leading "v"',
-            version = 'v1.2.3',
-            want = { major = 1, minor = 2, patch = 3 },
-          },
-          {
-            desc = 'a valid version with leading "v" and whitespace',
-            version = '  v1.2.3',
-            want = { major = 1, minor = 2, patch = 3 },
-          },
-          {
-            desc = 'a valid version with leading "v" and trailing whitespace',
-            version = 'v1.2.3  ',
-            want = { major = 1, minor = 2, patch = 3 },
-          },
-          {
-            desc = 'a version with a prerelease',
-            version = '1.2.3-alpha',
-            want = { major = 1, minor = 2, patch = 3, prerelease = 'alpha' },
-          },
-          {
-            desc = 'a version with a prerelease with additional identifiers',
-            version = '1.2.3-alpha.1',
-            want = { major = 1, minor = 2, patch = 3, prerelease = 'alpha.1' },
-          },
-          {
-            desc = 'a version with a build',
-            version = '1.2.3+build.15',
-            want = { major = 1, minor = 2, patch = 3, build = 'build.15' },
-          },
-          {
-            desc = 'a version with a prerelease and build',
-            version = '1.2.3-rc1+build.15',
-            want = {
-              major = 1,
-              minor = 2,
-              patch = 3,
-              prerelease = 'rc1',
-              build = 'build.15',
-            },
-          },
-        }
-        for _, tc in ipairs(testcases) do
-          it(
-            string.format('returns correct table for %q: version = %q', tc.desc, tc.version),
-            function()
-              eq(tc.want, version.parse(tc.version, { strict = true }))
-            end
-          )
-        end
-      end)
-
-      describe('strict = false', function()
-        local testcases = {
-          {
-            desc = 'a version missing patch version',
-            version = '1.2',
-            want = { major = 1, minor = 2, patch = 0 },
-          },
-          {
-            desc = 'a version missing minor and patch version',
-            version = '1',
-            want = { major = 1, minor = 0, patch = 0 },
-          },
-          {
-            desc = 'a version missing patch version with prerelease',
-            version = '1.1-0',
-            want = { major = 1, minor = 1, patch = 0, prerelease = '0' },
-          },
-          {
-            desc = 'a version missing minor and patch version with prerelease',
-            version = '1-1.0',
-            want = { major = 1, minor = 0, patch = 0, prerelease = '1.0' },
-          },
-        }
-        for _, tc in ipairs(testcases) do
-          it(
-            string.format('returns correct table for %q: version = %q', tc.desc, tc.version),
-            function()
-              eq(tc.want, version.parse(tc.version, { strict = false }))
-            end
-          )
-        end
-      end)
-    end)
-
-    describe('errors', function()
-      describe('returns nil', function()
-        local testcases = {
-          { desc = 'a word', version = 'foo' },
-          { desc = 'an empty string', version = '' },
-          { desc = 'trailing period character', version = '0.0.0.' },
-          { desc = 'leading period character', version = '.0.0.0' },
-          { desc = 'negative major version', version = '-1.0.0' },
-          { desc = 'negative minor version', version = '0.-1.0' },
-          { desc = 'negative patch version', version = '0.0.-1' },
-          { desc = 'leading invalid string', version = 'foobar1.2.3' },
-          { desc = 'trailing invalid string', version = '1.2.3foobar' },
-          { desc = 'an invalid prerelease', version = '1.2.3-%?' },
-          { desc = 'an invalid build', version = '1.2.3+%?' },
-          { desc = 'build metadata before prerelease', version = '1.2.3+build.0-rc1' },
-        }
-        for _, tc in ipairs(testcases) do
-          it(string.format('for %s: version = %s', tc.desc, tostring(tc.version)), function()
-            eq(nil, version.parse(tc.version, { strict = true }))
-          end)
-        end
-      end)
-
-      describe('raises error', function()
-        local testcases = {
-          { desc = 'no parameters' },
-          { desc = 'nil', version = nil },
-          { desc = 'a number', version = 0 },
-          { desc = 'a float', version = 0.01 },
-          { desc = 'a table', version = {} },
-        }
-        for _, tc in ipairs(testcases) do
-          it(string.format('for %s: version = %s', tc.desc, tostring(tc.version)), function()
-            matches(
-              string.format('invalid version: "%s"', tostring(tc.version)),
-              pcall_err(function()
-                version.parse(tc.version, { strict = true })
-              end)
-            )
-          end)
-        end
-      end)
-    end)
-  end)
-
-  describe('eq', function()
-    describe('valid versions', function()
+    describe('strict=true', function()
       local testcases = {
         {
-          version_1 = '1.0.0',
-          version_2 = '1.0.0',
-          want = true,
-        },
-        {
-          version_1 = '1.0.0',
-          version_2 = 'v1.0.0',
-          want = true,
-        },
-        {
-          version_1 = '1.0.0',
-          version_2 = '1.0',
-          want = true,
+          desc = 'version without leading "v"',
+          version = '10.20.123',
+          want = {
+            major = 10,
+            minor = 20,
+            patch = 123,
+            prerelease = nil,
+            build = nil,
+          },
         },
         {
-          version_1 = '1.0.0',
-          version_2 = '1',
-          want = true,
+          desc = 'valid version with leading "v"',
+          version = 'v1.2.3',
+          want = { major = 1, minor = 2, patch = 3 },
         },
         {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.0-alpha',
-          want = true,
+          desc = 'valid version with leading "v" and whitespace',
+          version = '  v1.2.3',
+          want = { major = 1, minor = 2, patch = 3 },
         },
         {
-          version_1 = '1.0.0-alpha',
-          version_2 = 'v1.0.0-alpha',
-          want = true,
+          desc = 'valid version with leading "v" and trailing whitespace',
+          version = 'v1.2.3  ',
+          want = { major = 1, minor = 2, patch = 3 },
         },
         {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.0-alpha+build.5',
-          want = true,
+          desc = 'version with prerelease',
+          version = '1.2.3-alpha',
+          want = { major = 1, minor = 2, patch = 3, prerelease = 'alpha' },
         },
         {
-          version_1 = '1.0.0-alpha.1',
-          version_2 = '1.0.0-alpha.1+build.5',
-          want = true,
+          desc = 'version with prerelease with additional identifiers',
+          version = '1.2.3-alpha.1',
+          want = { major = 1, minor = 2, patch = 3, prerelease = 'alpha.1' },
         },
         {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.0-alpha.1',
-          want = false,
+          desc = 'version with build',
+          version = '1.2.3+build.15',
+          want = { major = 1, minor = 2, patch = 3, build = 'build.15' },
         },
         {
-          version_1 = '1.0.0',
-          version_2 = '2.0.0',
-          want = false,
+          desc = 'version with prerelease and build',
+          version = '1.2.3-rc1+build.15',
+          want = {
+            major = 1,
+            minor = 2,
+            patch = 3,
+            prerelease = 'rc1',
+            build = 'build.15',
+          },
         },
       }
       for _, tc in ipairs(testcases) do
-        it(string.format('returns %s for %s = %s', tc.want, tc.version_1, tc.version_2), function()
-          eq(tc.want, version.eq(tc.version_1, tc.version_2))
-        end)
+        it(
+          string.format('for %q: version = %q', tc.desc, tc.version),
+          function()
+            eq(tc.want, version.parse(tc.version, { strict = true }))
+          end
+        )
       end
     end)
 
-    describe('errors', function()
+    describe('strict=false', function()
       local testcases = {
         {
-          version_1 = '',
-          version_2 = '1.0.0',
-          err_version = '',
+          desc = 'version missing patch version',
+          version = '1.2',
+          want = { major = 1, minor = 2, patch = 0 },
         },
         {
-          version_1 = '1.0.0',
-          version_2 = '',
-          err_version = '',
+          desc = 'version missing minor and patch version',
+          version = '1',
+          want = { major = 1, minor = 0, patch = 0 },
         },
         {
-          version_1 = '',
-          version_2 = '',
-          err_version = '',
+          desc = 'version missing patch version with prerelease',
+          version = '1.1-0',
+          want = { major = 1, minor = 1, patch = 0, prerelease = '0' },
         },
         {
-          version_1 = '1.0.0',
-          version_2 = 'foo',
-          err_version = 'foo',
+          desc = 'version missing minor and patch version with prerelease',
+          version = '1-1.0',
+          want = { major = 1, minor = 0, patch = 0, prerelease = '1.0' },
         },
       }
       for _, tc in ipairs(testcases) do
-        it(string.format('for %s = %s', tc.version_1, tc.version_2), function()
-          matches(
-            string.format('invalid version: "%s"', tc.err_version),
-            pcall_err(function()
-              version.eq(tc.version_1, tc.version_2)
-            end)
-          )
-        end)
+        it(
+          string.format('for %q: version = %q', tc.desc, tc.version),
+          function()
+            eq(tc.want, version.parse(tc.version, { strict = false }))
+          end
+        )
       end
     end)
-  end)
 
-  describe('lt', function()
-    describe('valid versions', function()
+    describe('invalid semver', function()
       local testcases = {
-        {
-          version_1 = '1.0.0',
-          version_2 = '1.0.1',
-          want = true,
-        },
-        {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.1',
-          want = true,
-        },
-        {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.1-beta',
-          want = true,
-        },
-        {
-          version_1 = '1.0.1',
-          version_2 = '1.0.0',
-          want = false,
-        },
-        {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.0-alpha',
-          want = false,
-        },
-        {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.0-alpha+build.5',
-          want = false,
-        },
-        {
-          version_1 = '1.0.0-alpha+build.4',
-          version_2 = '1.0.0-alpha+build.5',
-          want = false,
-        },
+        { desc = 'a word', version = 'foo' },
+        { desc = 'empty string', version = '' },
+        { desc = 'trailing period character', version = '0.0.0.' },
+        { desc = 'leading period character', version = '.0.0.0' },
+        { desc = 'negative major version', version = '-1.0.0' },
+        { desc = 'negative minor version', version = '0.-1.0' },
+        { desc = 'negative patch version', version = '0.0.-1' },
+        { desc = 'leading invalid string', version = 'foobar1.2.3' },
+        { desc = 'trailing invalid string', version = '1.2.3foobar' },
+        { desc = 'an invalid prerelease', version = '1.2.3-%?' },
+        { desc = 'an invalid build', version = '1.2.3+%?' },
+        { desc = 'build metadata before prerelease', version = '1.2.3+build.0-rc1' },
       }
       for _, tc in ipairs(testcases) do
-        it(
-          string.format('returns %s for %s < %s', tostring(tc.want), tc.version_1, tc.version_2),
-          function()
-            eq(tc.want, version.lt(tc.version_1, tc.version_2))
-          end
-        )
+        it(string.format('(%s): %s', tc.desc, quote_empty(tc.version)), function()
+          eq(nil, version.parse(tc.version, { strict = true }))
+        end)
       end
     end)
 
-    describe('errors', function()
+    describe('invalid shape', function()
       local testcases = {
-        {
-          version_1 = '',
-          version_2 = '1.0.0',
-          err_version = '',
-        },
-        {
-          version_1 = '1.0.0',
-          version_2 = '',
-          err_version = '',
-        },
-        {
-          version_1 = '',
-          version_2 = '',
-          err_version = '',
-        },
+        { desc = 'no parameters' },
+        { desc = 'nil', version = nil },
+        { desc = 'number', version = 0 },
+        { desc = 'float', version = 0.01 },
+        { desc = 'table', version = {} },
       }
       for _, tc in ipairs(testcases) do
-        it(string.format('for %s < %s', tc.version_1, tc.version_2), function()
-          matches(
-            string.format('invalid version: "%s"', tc.err_version),
-            pcall_err(function()
-              version.lt(tc.version_1, tc.version_2)
-            end)
-          )
+        it(string.format('(%s): %s', tc.desc, tostring(tc.version)), function()
+          matches(string.format('invalid version: "%s"', tostring(tc.version)),
+            pcall_err(version.parse, tc.version, { strict = true }))
         end)
       end
     end)
   end)
 
-  describe('gt', function()
-    describe('valid versions', function()
-      local testcases = {
-        {
-          version_1 = '1.0.1',
-          version_2 = '1.0.0',
-          want = true,
-        },
-        {
-          version_1 = '1.0.1',
-          version_2 = '1.0.1-alpha',
-          want = true,
-        },
+  describe('eq()', function()
+    local testcases = {
+      {
+        v1 = '1.0.0',
+        v2 = '1.0.0',
+        want = true,
+      },
+      {
+        v1 = '1.0.0',
+        v2 = 'v1.0.0',
+        want = true,
+      },
+      {
+        v1 = '1.0.0',
+        v2 = '1.0',
+        want = true,
+      },
+      {
+        v1 = '1.0.0',
+        v2 = '1',
+        want = true,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.0-alpha',
+        want = true,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = 'v1.0.0-alpha',
+        want = true,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.0-alpha+build.5',
+        want = true,
+      },
+      {
+        v1 = '1.0.0-alpha.1',
+        v2 = '1.0.0-alpha.1+build.5',
+        want = true,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.0-alpha.1',
+        want = false,
+      },
+      {
+        v1 = '1.0.0',
+        v2 = '2.0.0',
+        want = false,
+      },
+    }
+
+    for _, tc in ipairs(testcases) do
+      it(string.format('returns %s for %s = %s', tostring(tc.want), tc.v1, tc.v2), function()
+        eq(tc.want, version.eq(tc.v1, tc.v2))
+      end)
+    end
+
+    describe('fails', function()
+      local failtests = {
         {
-          version_1 = '1.0.0',
-          version_2 = '1.0.1',
-          want = false,
+          v1 = '',
+          v2 = '1.0.0',
+          err_version = '',
         },
         {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.1',
-          want = false,
+          v1 = '1.0.0',
+          v2 = '',
+          err_version = '',
         },
         {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.1-beta',
-          want = false,
+          v1 = '',
+          v2 = '',
+          err_version = '',
         },
         {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.0-alpha',
-          want = false,
+          v1 = '1.0.0',
+          v2 = 'foo',
+          err_version = 'foo',
         },
+      }
+      for _, tc in ipairs(failtests) do
+        it(string.format('for %s = %s', quote_empty(tc.v1), quote_empty(tc.v2)), function()
+          matches(string.format('invalid version: "%s"', tc.err_version),
+            pcall_err(version.eq, tc.v1, tc.v2))
+        end)
+      end
+    end)
+  end)
+
+  describe('lt()', function()
+    local testcases = {
+      {
+        v1 = '1.0.0',
+        v2 = '1.0.1',
+        want = true,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.1',
+        want = true,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.1-beta',
+        want = true,
+      },
+      {
+        v1 = '1.0.1',
+        v2 = '1.0.0',
+        want = false,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.0-alpha',
+        want = false,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.0-alpha+build.5',
+        want = false,
+      },
+      {
+        v1 = '1.0.0-alpha+build.4',
+        v2 = '1.0.0-alpha+build.5',
+        want = false,
+      },
+    }
+    for _, tc in ipairs(testcases) do
+      it(string.format('returns %s for %s < %s', tostring(tc.want), tc.v1, tc.v2), function()
+        eq(tc.want, version.lt(tc.v1, tc.v2))
+      end)
+    end
+
+    describe('fails', function()
+      local failtests = {
         {
-          version_1 = '1.0.0-beta',
-          version_2 = '1.0.0-alpha',
-          want = true,
+          v1 = '',
+          v2 = '1.0.0',
+          err_version = '',
         },
         {
-          version_1 = '1.0.0-alpha',
-          version_2 = '1.0.0-alpha+build.5',
-          want = false,
+          v1 = '1.0.0',
+          v2 = '',
+          err_version = '',
         },
         {
-          version_1 = '1.0.0-alpha+build.4',
-          version_2 = '1.0.0-alpha+build.5',
-          want = false,
+          v1 = '',
+          v2 = '',
+          err_version = '',
         },
       }
-      for _, tc in ipairs(testcases) do
-        it(string.format('returns %s for %s > %s', tc.want, tc.version_1, tc.version_2), function()
-          eq(tc.want, version.gt(tc.version_1, tc.version_2))
+      for _, tc in ipairs(failtests) do
+        it(string.format('for %s < %s', quote_empty(tc.v1), quote_empty(tc.v2)), function()
+          matches(string.format('invalid version: "%s"', tc.err_version),
+            pcall_err(version.lt, tc.v1, tc.v2))
         end)
       end
     end)
+  end)
 
-    describe('errors', function()
-      local testcases = {
+  describe('gt()', function()
+    local testcases = {
+      {
+        v1 = '1.0.1',
+        v2 = '1.0.0',
+        want = true,
+      },
+      {
+        v1 = '1.0.1',
+        v2 = '1.0.1-alpha',
+        want = true,
+      },
+      {
+        v1 = '1.0.0',
+        v2 = '1.0.1',
+        want = false,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.1',
+        want = false,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.1-beta',
+        want = false,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.0-alpha',
+        want = false,
+      },
+      {
+        v1 = '1.0.0-beta',
+        v2 = '1.0.0-alpha',
+        want = true,
+      },
+      {
+        v1 = '1.0.0-alpha',
+        v2 = '1.0.0-alpha+build.5',
+        want = false,
+      },
+      {
+        v1 = '1.0.0-alpha+build.4',
+        v2 = '1.0.0-alpha+build.5',
+        want = false,
+      },
+    }
+
+    for _, tc in ipairs(testcases) do
+      it(string.format('returns %s for %s > %s', tostring(tc.want), tc.v1, tc.v2), function()
+        eq(tc.want, version.gt(tc.v1, tc.v2))
+      end)
+    end
+
+    describe('fails', function()
+      local failtests = {
         {
-          version_1 = '',
-          version_2 = '1.0.0',
+          v1 = '',
+          v2 = '1.0.0',
           err_version = '',
         },
         {
-          version_1 = '1.0.0',
-          version_2 = '',
+          v1 = '1.0.0',
+          v2 = '',
           err_version = '',
         },
         {
-          version_1 = '',
-          version_2 = '',
+          v1 = '',
+          v2 = '',
           err_version = '',
         },
       }
-      for _, tc in ipairs(testcases) do
-        it(string.format('for %s < %s', tc.version_1, tc.version_2), function()
-          matches(
-            string.format('invalid version: "%s"', tc.err_version),
-            pcall_err(function()
-              version.gt(tc.version_1, tc.version_2)
-            end)
-          )
+      for _, tc in ipairs(failtests) do
+        it(string.format('for %s < %s', quote_empty(tc.v1), quote_empty(tc.v2)), function()
+          matches(string.format('invalid version: "%s"', tc.err_version),
+            pcall_err(version.gt, tc.v1, tc.v2))
         end)
       end
     end)