diff --git a/busted/outputHandlers/json.lua b/busted/outputHandlers/json.lua
index 97a07f37..ee915a8b 100644
--- a/busted/outputHandlers/json.lua
+++ b/busted/outputHandlers/json.lua
@@ -14,12 +14,26 @@ return function(options)
       errors = handler.errors,
       duration = handler.getDuration()
     }
-    local ok, result = pcall(json.encode, error_info)
+
+    for _, test in ipairs(handler.pendings) do
+      test.element.attributes.default_fn = nil -- functions cannot be encoded into json
+    end
+
+    local ok, result = pcall(json.encode, error_info, {
+      exception = function(reason, value, state, default_reason)
+        local state_short = table.concat(state.buffer, "")
+        state_short = ("... %s %s"):format(state_short:sub(#state_short - 100), tostring(state.exception))
+
+        local err_msg = (default_reason .. " in (%s)\n"):format(state_short)
+        io.stderr:write(err_msg)
+      end,
+    })
 
     if ok then
       io_write(result)
     else
       io_write("Failed to encode test results to json: " .. result)
+      os.exit(1)
     end
 
     io_write("\n")
diff --git a/spec/cl_output_json.lua b/spec/cl_output_json.lua
new file mode 100644
index 00000000..3d9cf87a
--- /dev/null
+++ b/spec/cl_output_json.lua
@@ -0,0 +1,5 @@
+-- supporting testfile; belongs to 'cl_output_json_spec.lua'
+
+describe("spec with non string attributes", function()
+  non_string_spec('throws an error when encoded into json')
+end)
diff --git a/spec/cl_output_json_helper.lua b/spec/cl_output_json_helper.lua
new file mode 100644
index 00000000..b55188e7
--- /dev/null
+++ b/spec/cl_output_json_helper.lua
@@ -0,0 +1,9 @@
+return function(busted, helper, options)
+  busted.register('non_string_spec', busted.pending, {
+    default_fn = function() end,
+    non_string_attribute_1 = function() end,
+    non_string_attribute_2 = function() end,
+    non_string_attribute_3 = function() end
+  })
+  return true
+end
diff --git a/spec/cl_output_json_spec.lua b/spec/cl_output_json_spec.lua
new file mode 100644
index 00000000..c69b0cd2
--- /dev/null
+++ b/spec/cl_output_json_spec.lua
@@ -0,0 +1,35 @@
+local utils = require 'pl.utils'
+local path = require 'pl.path'
+local busted_cmd = path.is_windows and 'lua bin/busted' or 'eval $(luarocks path) && bin/busted'
+
+-- if exitcode >256, then take MSB as exit code
+local modexit = function(exitcode)
+  if exitcode > 255 then
+    return math.floor(exitcode / 256), exitcode - math.floor(exitcode / 256) * 256
+  else
+    return exitcode
+  end
+end
+
+local execute = function(cmd)
+  local success, exitcode, out, err = utils.executeex(cmd)
+  return not not success, modexit(exitcode), out, err
+end
+
+describe('Tests the busted json output', function()
+  it('encodes pending tests', function()
+    local success, exit_code, out, err = execute(busted_cmd .. ' ' .. '--pattern=cl_pending.lua$ --output=busted/outputHandlers/json.lua')
+
+    assert.is_true(success)
+    assert.is_true(exit_code == 0)
+    assert.is_true(err == '')
+  end)
+
+  it('notifies with error if results cannot be encoded', function()
+    local success, exit_code, out, err = execute(busted_cmd .. ' --helper=spec/cl_output_json_helper.lua spec/cl_output_json.lua --output=busted/outputHandlers/json.lua')
+
+    assert.is_false(success)
+    assert.is_true(exit_code ~= 0)
+    assert.is_truthy(err:find("type 'function' is not supported by JSON"))
+  end)
+end)