the new evolved.locate public function

ref: #23

develop/testing/locate_tests.lua

@@ -0,0 +1,48 @@
+local evo = require 'evolved'
+
+do
+    local e1, e2, f1, f2 = evo.id(4)
+
+    do
+        local chunk, place = evo.locate(e1)
+        assert(chunk == nil and place == 0)
+    end
+
+    evo.set(e1, f1, 42)
+
+    do
+        local chunk, place = evo.locate(e1)
+        assert(chunk and chunk == evo.chunk(f1) and place == 1)
+        assert(chunk:components(f1)[place] == 42)
+
+        chunk, place = evo.locate(e2)
+        assert(chunk == nil and place == 0)
+    end
+
+    evo.set(e1, f2, 'hello')
+
+    do
+        local chunk, place = evo.locate(e1)
+        assert(chunk and chunk == evo.chunk(f1, f2) and place == 1)
+        assert(chunk:components(f1)[place] == 42)
+        assert(chunk:components(f2)[place] == 'hello')
+
+        chunk, place = evo.locate(e2)
+        assert(chunk == nil and place == 0)
+    end
+
+    evo.set(e2, f1, 84)
+    evo.set(e2, f2, 'world')
+
+    do
+        local chunk, place = evo.locate(e1)
+        assert(chunk and chunk == evo.chunk(f1, f2) and place == 1)
+        assert(chunk:components(f1)[place] == 42)
+        assert(chunk:components(f2)[place] == 'hello')
+
+        chunk, place = evo.locate(e2)
+        assert(chunk and chunk == evo.chunk(f1, f2) and place == 2)
+        assert(chunk:components(f1)[place] == 84)
+        assert(chunk:components(f2)[place] == 'world')
+    end
+end