samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/declerrors.t

@@ -0,0 +1,29 @@
+function failit(fn,err)
+	local success,msg = pcall(fn)
+	if success then
+		error("failed to fail.",2)
+	elseif not string.match(msg,err or "Errors reported during") then
+		error("failed wrong: "..msg,2)
+	end
+end
+
+
+failit(function()
+local A = {}
+terra A:foo() end
+end,"expected a struct")
+
+
+failit(function()
+terra A.b() end
+end,"failed attempting to index field")
+
+failit(function()
+terra A.b.c() end
+end,"failed attempting to index field")
+
+
+failit(function()
+local A = 4
+struct A.b {}
+end,"failed attempting to index field")