Improve output of Lua tests (#5499)

This makes use of tasty-lua, a package to write tests in Lua
and integrate the results into Tasty output. Test output becomes
more informative: individual tests and test groups become visible
in test output. Failures are reported with helpful error messages.

1 files changed, 58 insertions, 0 deletions

diff --git a/test/lua/module/pandoc.lua b/test/lua/module/pandoc.lua
new file mode 100644
index 000000000..b9509cdb6
--- /dev/null
+++ b/test/lua/module/pandoc.lua
@@ -0,0 +1,58 @@
+local tasty = require 'tasty'
+
+local test = tasty.test_case
+local group = tasty.test_group
+local assert = tasty.assert
+
+function os_is_windows ()
+  return package.config:sub(1,1) == '\\'
+end
+
+return {
+  group 'pipe' {
+    test('external string processing', function ()
+      if os_is_windows() then
+        local pipe_result = pandoc.pipe('find', {'hi'}, 'hi')
+        assert.are_equal('hi', pipe_result:match '%a+')
+      else
+        local pipe_result = pandoc.pipe('tr', {'a', 'b'}, 'abc')
+        assert.are_equal('bbc', pipe_result:match '%a+')
+      end
+    end),
+    test('failing pipe', function ()
+      if os_is_windows() then
+        local success, err = pcall(pandoc.pipe, 'find', {'/a'}, 'hi')
+        assert.is_falsy(success)
+        assert.are_equal('find', err.command)
+        assert.is_truthy(err.error_code ~= 0)
+      else
+        local success, err = pcall(pandoc.pipe, 'false', {}, 'abc')
+        assert.is_falsy(success)
+        assert.are_equal('false', err.command)
+        assert.are_equal(1, err.error_code)
+        assert.are_equal('', err.output)
+      end
+    end)
+  },
+
+  group 'read' {
+    test('Markdown', function ()
+      local valid_markdown = '*Hello*, World!\n'
+      local expected = pandoc.Pandoc({
+          pandoc.Para {
+            pandoc.Emph { pandoc.Str 'Hello' },
+            pandoc.Str ',',
+            pandoc.Space(),
+            pandoc.Str 'World!'
+          }
+      })
+      assert.are_same(expected, pandoc.read(valid_markdown))
+    end),
+    test('failing read', function ()
+      assert.error_matches(
+        function () pandoc.read('foo', 'nosuchreader') end,
+        'Unknown reader: nosuchreader'
+      )
+    end)
+  },
+}