Add specs for GC

spec/gc_spec.lua

@@ -0,0 +1,116 @@
+local GC = require('apicast.gc')
+
+describe('GC', function()
+  describe('.set_metatable_gc', function()
+    it('enables GC on a table', function()
+      local test_table = { 1, 2, 3 }
+      local test_metatable = { __gc = function() end }
+      spy.on(test_metatable, '__gc')
+
+      assert(GC.set_metatable_gc(test_table, test_metatable))
+      collectgarbage()
+
+      assert.spy(test_metatable.__gc).was_called()
+    end)
+
+    it('returns an object where we can access, add, and delete elements', function()
+      local test_table = { 1, 2, 3, some_key = 'some_val' }
+      local test_metatable = { __gc = function() end }
+
+      local table_with_gc = GC.set_metatable_gc(test_table, test_metatable)
+
+      assert.equals(3, #table_with_gc)
+      assert.equals(1, table_with_gc[1])
+      assert.equals('some_val', table_with_gc.some_key)
+
+      table_with_gc.new_key = 'new_val'
+      assert.equals('new_val', table_with_gc.new_key)
+
+      table_with_gc.new_key = nil
+      assert.is_nil(table_with_gc.new_key)
+    end)
+
+    it('returns an object that responds to ipairs', function()
+      local test_table = { 1, 2, 3, some_key = 'some_val' }
+      local test_metatable = { __gc = function() end }
+
+      local table_with_gc = GC.set_metatable_gc(test_table, test_metatable)
+
+      local res = {}
+      for _, val in ipairs(table_with_gc) do
+        table.insert(res, val)
+      end
+
+      assert.same({ 1, 2, 3 }, res)
+    end)
+
+    it('returns an object that respons to pairs', function()
+      local test_table = { 1, 2, 3, some_key = 'some_val' }
+      local test_metatable = { __gc = function() end }
+
+      local table_with_gc = GC.set_metatable_gc(test_table, test_metatable)
+
+      local res = {}
+      for k, v in pairs(table_with_gc) do
+        res[k] = v
+      end
+
+      assert.same({ [1] = 1, [2] = 2, [3] = 3, some_key = 'some_val' }, res)
+    end)
+
+    it('returns an object that respects the __call in the mt of the original table', function()
+      local test_table = { 1, 2, 3 }
+      local test_metatable = {
+        __gc = function() end,
+        __call = function(_, ...)
+          local res = 0
+
+          for _, val in ipairs(table.pack(...)) do
+            res = res + val
+          end
+
+          return res
+        end
+      }
+
+      local table_with_gc = GC.set_metatable_gc(test_table, test_metatable)
+
+      assert.equals(3, table_with_gc(1, 2))
+    end)
+
+    it('returns an object that respects the __tostring in the mt of the original table', function()
+      local test_table = { 1, 2, 3 }
+      local test_metatable = {
+        __gc = function() end,
+        __tostring = function() return '123' end
+      }
+
+      local table_with_gc = GC.set_metatable_gc(test_table, test_metatable)
+
+      assert.equals('123', tostring(table_with_gc))
+    end)
+
+    it('returns an object that returns an error when it cannot be called', function()
+      local test_table = { 1, 2, 3 }
+      local test_metatable = { __gc = function() end }
+
+      local table_with_gc = GC.set_metatable_gc(test_table, test_metatable)
+
+      local ok, err = pcall(table_with_gc, 1, 2)
+
+      assert.falsy(ok)
+
+      -- Test that the error is meaningful
+      assert.equals('attempt to call a table value', err)
+    end)
+
+    it('returns an object that has as a metatable the one sent in the params', function()
+      local test_table = { 1, 2, 3 }
+      local test_metatable = { __gc = function() end }
+
+      local table_with_gc = GC.set_metatable_gc(test_table, test_metatable)
+
+      assert.same(test_metatable, getmetatable(table_with_gc))
+    end)
+  end)
+end)