added tests related to help, improved help generation

spec/help_spec.lua

@@ -0,0 +1,104 @@
+local argparse = require "argparse"
+
+describe("tests related to help message generation", function()
+   it("creates correct help message for empty parser", function()
+      local parser = argparse.parser "foo"
+      assert.equal(table.concat({
+         "Usage: foo [-h]",
+         "",
+         "Options: ",
+         "   -h, --help            Show this help message and exit. "
+      }, "\r\n"), parser:prepare():get_help())
+   end)
+
+   it("creates correct help message for arguments", function()
+      local parser = argparse.parser "foo"
+      parser:argument "first"
+      parser:argument "second-and-third"
+         :args "2"
+      parser:argument "maybe-fourth"
+         :args "?"
+      parser:argument "others"
+         :description "Optional. "
+         :args "*"
+
+      assert.equal(table.concat({
+         "Usage: foo [-h] <first> <second-and-third> <second-and-third> [<maybe-fourth>] [<others>] ...",
+         "",
+         "Arguments: ",
+         "   first",
+         "   second-and-third",
+         "   maybe-fourth",
+         "   others                Optional. ",
+         "",
+         "Options: ",
+         "   -h, --help            Show this help message and exit. "
+      }, "\r\n"), parser:prepare():get_help())
+   end)
+
+   it("creates correct help message for options", function()
+      local parser = argparse.parser "foo"
+      parser:flag "-q" "--quiet"
+      parser:option "--from"
+         :count "1"
+         :target "server"
+      parser:option "--config"
+
+      assert.equal(table.concat({
+         "Usage: foo [-q] --from <server> [--config <config>] [-h]",
+         "",
+         "Options: ",
+         "   -q, --quiet",
+         "   --from <server>",
+         "   --config <config>",
+         "   -h, --help            Show this help message and exit. "
+      }, "\r\n"), parser:prepare():get_help())
+   end)
+
+   it("creates correct help message for commands", function()
+      local parser = argparse.parser "foo"
+      parser:flag "-q" "--quiet"
+      local run = parser:command "run"
+         :description "Run! "
+      run:option "--where"
+
+      assert.equal(table.concat({
+         "Usage: foo [-q] [-h] [<command>] ...",
+         "",
+         "Options: ",
+         "   -q, --quiet",
+         "   -h, --help            Show this help message and exit. ",
+         "",
+         "Commands: ",
+         "   run                   Run! "
+      }, "\r\n"), parser:prepare():get_help())
+   end)
+
+   it("creates correct help message for subcommands", function()
+      local parser = argparse.parser "foo"
+      parser:flag "-q" "--quiet"
+      local run = parser:command "run"
+      run:option "--where"
+
+      parser:prepare()
+
+      assert.equal(table.concat({
+         "Usage: foo run [--where <where>] [-h]",
+         "",
+         "Options: ",
+         "   --where <where>",
+         "   -h, --help            Show this help message and exit. ",
+      }, "\r\n"), run:prepare():get_help())
+   end)
+
+   it("uses message provided by user", function()
+      local parser = argparse.parser "foo"
+         :help "I don't like your format of help messages"
+      parser:flag "-q" "--quiet"
+
+      assert.equal(
+         [=[I don't like your format of help messages]=],
+         parser:prepare():get_help()
+      )
+   end)
+end)

src/argparse.lua

@@ -341,16 +341,16 @@ function Parser:get_usage()
 end
 
 local function make_two_columns(s1, s2)
+   if s2 == "" then
+      return "   " .. s1
+   end
+
    if #s1 < 22 then
       return "   " .. s1 .. (" "):rep(22 - #s1) .. s2
-   else
-      if s2 == "" then
-         return "   " .. s1
    else
       return "   " .. s1 .. "\r\n" .. (" "):rep(25) .. s2
    end
 end
-end
 
 local function make_description(element)
    if element._default then