Add README

README

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+minetest-worldtest - Minetest world compatibility tester
+=========================================================
+WTFPL - 2012 Perttu Ahola <celeron55@gmail.com>
+
+1. Builds a number of Minetest versions as defined in rules.d/
+2. Creates and reads worlds with them and reports errors
+
+Patches in rules.d/$tag/*.patch are applied to each version. The patches are supposed to modify the built minetestserver so that it will, once started:
+1. Load or generate all the MapBlocks touching (0,0,0)
+2. After loading, read nodes and check if they are correctly set
+  - Create a new file worldtest_result.txt for results
+  - If a test passes, print a line starting with GOOD:, otherwise print a line starting with BAD:
+3. Set the nodes in the certain formation
+4. Save and quit
+
+The formation of nodes used is:
+- 3x5x3 hollow box made of nyan cats, having
+- a torch at the topmost inside node (0,2,0), the light value of day and night being 13,
+- a glass block at the middle (0,1,0), light being 12
+- air at the bottom (0,0,0), light being 11, and
+- a sign at the node at (0,0,2); the text of the sign is "Foo Bar".
+
+Example output
+===============
+
+Result summary:
+== 0.3.1 returns all bad for non-existent world
+== 0.3.1 returns all good for self-generated world
+== 0.4.dev-20120122-1 returns all bad for non-existent world
+== 0.4.dev-20120122-1 returns all good for self-generated world
+== 0.4.dev-20120122-1 returns all good for world generated by 0.3.1
+== 0.4.dev-20120408 returns all bad for non-existent world
+== 0.4.dev-20120408 returns all good for self-generated world
+== 0.4.dev-20120408 returns all good for world generated by 0.3.1
+== 0.4.dev-20120408 returns all good for world generated by 0.4.dev-20120122-1
+== 0.4.dev-20120606 returns all bad for non-existent world
+== 0.4.dev-20120606 returns all good for self-generated world
+== 0.4.dev-20120606 returns all good for world generated by 0.3.1
+== 0.4.dev-20120606 returns all good for world generated by 0.4.dev-20120122-1
+== 0.4.dev-20120606 returns all good for world generated by 0.4.dev-20120408
+== 0.4.1 returns all bad for non-existent world
+== 0.4.1 returns all good for self-generated world
+== 0.4.1 returns all good for world generated by 0.3.1
+== 0.4.1 returns all good for world generated by 0.4.dev-20120122-1
+== 0.4.1 returns all good for world generated by 0.4.dev-20120408
+== 0.4.1 returns all good for world generated by 0.4.dev-20120606
+== master returns all bad for non-existent world
+== master returns all good for self-generated world
+EE master returns some bad for world generated by 0.3.1
+BAD: (-1,-1,-1) should be "default:nyancat", is ""
+BAD: (0,3,0) should be "default:nyancat", is ""
+BAD: (0,1,0) should be "default:glass", is ""
+BAD: (0,1,0) should have day=12 night=12, has day=0 night=0
+== master returns all good for world generated by 0.4.dev-20120122-1
+== master returns all good for world generated by 0.4.dev-20120408
+== master returns all good for world generated by 0.4.dev-20120606
+== master returns all good for world generated by 0.4.1
+