1 files changed, 91 insertions, 0 deletions
diff --git a/test/lua/busted/context.lua b/test/lua/busted/context.lua
new file mode 100644
index 000000000..4cf0f3b53
--- /dev/null
+++ b/test/lua/busted/context.lua
@@ -0,0 +1,91 @@
+local tablex = require 'pl.tablex'
+
+local function save()
+  local g = {}
+  for k,_ in next, _G, nil do
+    g[k] = rawget(_G, k)
+  end
+  return {
+    gmt = getmetatable(_G),
+    g = g,
+    loaded = tablex.copy(package.loaded)
+  }
+end
+
+local function restore(state)
+  setmetatable(_G, state.gmt)
+  for k,_ in next, _G, nil do
+    rawset(_G, k, state.g[k])
+  end
+  for k,_ in pairs(package.loaded) do
+    package.loaded[k] = state.loaded[k]
+  end
+end
+
+return function()
+  local context = {}
+
+  local data = {}
+  local parents = {}
+  local children = {}
+  local stack = {}
+
+  function context.ref()
+    local ref = {}
+    local ctx = data
+
+    function ref.get(key)
+      if not key then return ctx end
+      return ctx[key]
+    end
+
+    function ref.set(key, value)
+      ctx[key] = value
+    end
+
+    function ref.clear()
+      data = {}
+      parents = {}
+      children = {}
+      stack = {}
+      ctx = data
+    end
+
+    function ref.attach(child)
+      if not children[ctx] then children[ctx] = {} end
+      parents[child] = ctx
+      table.insert(children[ctx], child)
+    end
+
+    function ref.children(parent)
+      return children[parent] or {}
+    end
+
+    function ref.parent(child)
+      return parents[child]
+    end
+
+    function ref.push(current)
+      if not parents[current] then error('Detached child. Cannot push.') end
+      if ctx ~= current and current.descriptor == 'file' then
+        current.state = save()
+      end
+      table.insert(stack, ctx)
+      ctx = current
+    end
+
+    function ref.pop()
+      local current = ctx
+      ctx = table.remove(stack)
+      if ctx ~= current and current.state then
+        restore(current.state)
+        current.state = nil
+      end
+      if not ctx then error('Context stack empty. Cannot pop.') end
+    end
+
+    return ref
+  end
+
+  return context
+end