tests: test the examples in the readme

Signed-off-by: Asbjørn Sloth Tønnesen <ast@2e8.dk>

1 files changed, 116 insertions, 0 deletions

diff --git a/test/readme.lua b/test/readme.lua
new file mode 100644
index 0000000..17f8312
--- /dev/null
+++ b/test/readme.lua
@@ -0,0 +1,116 @@
+local lpeg = require 'lpeg'
+local test = require 'test'
+local io = require 'io'
+
+local format = string.format
+local pack = table.pack
+local concat = table.concat
+
+local readme_parser
+do
+	local P = lpeg.P
+	local Ct = lpeg.Ct
+	local C = lpeg.C
+	local Cc = lpeg.Cc
+
+	local sp = P(' ')
+	local eq = P('=')
+	local nl = P('\n')
+	local div = P(' -- returns ')
+	local non_nl = P(1)-nl
+
+	local example = Ct(Cc('example') * C(((P(1)-(div+nl))^1)) * div * C(non_nl^1))
+	local assign_left = P('local ')^-1 * C(((P(1)-((sp^0 * eq)+nl))^1))
+	local assign_mid = sp^1 * eq * sp^1
+	local assign_right = C(non_nl^1)
+	local assignment = Ct(Cc('assignment') * assign_left * assign_mid * assign_right)
+	local indented_line = sp^2 * (example + assignment)
+	local anyline = non_nl^0
+	local line = indented_line + anyline
+
+	readme_parser = Ct((line * nl)^0 * line^-1 * -1)
+end
+
+local env = {
+	tostring = tostring,
+	require = require,
+}
+
+local function run(name, code)
+	local f = assert(load(code, name, 't', env))
+	local ret = pack(pcall(f))
+	if ret[1] then
+		return ret
+	else
+		print()
+		print('code:', code)
+		print('error:', ret[2])
+		print()
+		return { true, nil, n=3 }
+	end
+end
+
+local function run_example(name, code)
+	return run(name, format('return %s', code))
+end
+
+local function pack2str(t)
+	local new = {}
+	local n = t.n
+	for i=2,n do
+		local v = t[i]
+		local vt = type(v)
+		if vt == 'nil' then
+			new[i] = 'nil'
+		else
+			new[i] = format('%s "%s"', vt, v)
+		end
+	end
+	return concat(new, ', ', 2, n)
+end
+
+local function compare_packs(a, b)
+	local n = a.n
+	if n ~= b.n then return false end
+	for i=1,n do
+		local va = a[i]
+		local vb = b[i]
+		local vat = type(va)
+		local vbt = type(vb)
+		if vat ~= vbt then return false end
+		if va ~= vb then return false end
+	end
+	return true
+end
+
+local function hdl_assignment(line)
+	local code = format('%s = %s', line[2], line[3])
+	run('assignment', code)
+end
+
+local function hdl_example(line)
+	local t1 = line[2]
+	local t2 = line[3]
+	local r1 = run_example('left side', t1)
+	local r2 = run_example('right side', t2)
+	local errmsg = format('"%s" returns %s, not %s', t1, pack2str(r1), pack2str(r2))
+	assert(compare_packs(r1, r2), errmsg)
+end
+
+local handlers = {
+	assignment = hdl_assignment,
+	example = hdl_example,
+}
+
+local function readme_test()
+	local data = assert(io.open('README.rst', 'r')):read('*a')
+	local lines = assert(readme_parser:match(data))
+	for i=1,#lines do
+		local line = lines[i]
+		local kind = line[1]
+		local handler = handlers[kind]
+		handler(line)
+	end
+end
+
+return test.new(readme_test)