parser: Parse single options block

src/lib/autoload/a_04_backend.lua

+--[[
+Copyright 2016, CZ.NIC z.s.p.o. (http://www.nic.cz/)
+
+This file is part of the turris updater.
+
+Updater is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Updater is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Updater.  If not, see <http://www.gnu.org/licenses/>.
+]]--
+
+local error = error
+
+module "backend"
+
+--[[
+Parse a single block of mail-header-like records.
+Return as a table.
+]]--
+function parse_block(block)
+	local result = {}
+	local name
+	local value
+	local function store()
+		if name then
+			result[name] = value
+			name = nil
+			value = nil
+		end
+	end
+	for line in block:gmatch("[^\n]+") do
+		local n, v = line:match('^(%S+):%s*(.*)')
+		if n then
+			-- The beginning of the field
+			store()
+			name = n
+			value = v
+		elseif line:match('^%s') then
+			-- The continuation of a field
+			if not name then
+				error("Continuation at the beginning of block: " .. line)
+			end
+			value = value .. "\n" .. line
+		else
+			error("Malformed line: " .. line)
+		end
+	end
+	store()
+	return result
+end
+
+return _M

tests/Makefile.dir

@@ -16,7 +16,8 @@ C_TESTS := \
 	events \
 	interpreter
 
-LUA_TESTS := # No tests yet, but they'll come. The machinery has been tested with uncommited „empty“ test case.
+LUA_TESTS := \
+	backend
 
 define DO_C_TEST
 

tests/backend.lua

+--[[
+Copyright 2016, CZ.NIC z.s.p.o. (http://www.nic.cz/)
+
+This file is part of the turris updater.
+
+Updater is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Updater is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Updater.  If not, see <http://www.gnu.org/licenses/>.
+]]--
+
+require 'lunit'
+local B = require 'backend'
+
+module("backend-tests", package.seeall, lunit.testcase)
+
+-- Tests for the parse_block function
+function test_parse_block()
+	-- Simple case
+	assert_table_equal({
+		val1 = "value 1",
+		val2 = "value 2",
+		val3 = "value 3"
+	}, B.parse_block([[val1: value 1
+val2:  value 2
+val3:	value 3]]))
+	-- Continuations of fields
+	assert_table_equal({
+		val1 = [[value 1
+ line 2
+ line 3]],
+		val2 = "value 2"
+	}, B.parse_block([[val1: value 1
+ line 2
+ line 3
+val2: value 2]]))
+	-- Continuation on the first line, several ways
+	assert_error(function() B.parse_block(" x") end)
+	assert_error(function() B.parse_block(" x: y") end)
+	-- Some other strange lines
+	assert_error(function() B.parse_block("xyz") end)
+	assert_error(function() B.parse_block(" ") end)
+end

tests/lunit-launch/launch.lua

@@ -4,3 +4,13 @@ function launch(test)
 	local stats = lunit.main({test})
 	return stats.errors, stats.failed
 end
+
+function assert_table_equal(t1, t2)
+	local function cmp(t1, t2, name)
+		for k, v in pairs(t1) do
+			lunit.assert_equal(v, t2[k], "Values for key '" .. k .. "' differ: '" .. v .. "' vs '" .. t2[k] .. "'" .. name)
+		end
+	end
+	cmp(t1, t2, " pass 1")
+	cmp(t2, t1, " pass 2")
+end