lua-ln/spec/ln_spec.lua

local ln = require "ln"

describe("ln", function()
  describe("exports", function()
    it("has Logger", function()
      assert.truthy(ln.Logger)
    end)

    it("has default_logger", function()
      assert.truthy(ln.default_logger)
      assert.truthy(ln.default_logger.formatter)
      assert.truthy(ln.default_logger.filters)
    end)

    it("has LogfmtFormatter", function()
      assert.truthy(ln.LogfmtFormatter)
    end)

    it("has JSONFormatter", function()
      assert.truthy(ln.JSONFormatter)
    end)

    it("has log", function()
      assert.truthy(ln.log)
    end)

    it("has err", function()
      assert.truthy(ln.err)
    end)
  end)

  describe("default logger operations", function()
    local lgr = ln.default_logger
    local msg
    lgr.filters = {
      function(message) msg = message end,
    }
    
    it("can log", function()
      lgr:log {foo = "bar"}
      assert.truthy(string.find(msg, 'foo=bar'))
    end)

    it("can error", function()
      lgr:err("vibe check failed", {foo = "baz"})
      assert.truthy(string.find(msg, 'foo=baz'))
      assert.truthy(string.find(msg, 'vibe check failed'))
    end)

    it("takes multiple tables", function()
      lgr:log({foo = "bar"}, {baz = "boz"})
      assert.truthy(string.find(msg, 'foo=bar'))
      assert.truthy(string.find(msg, 'baz=boz'))
    end)

    it("lets you override the formatter", function()
      lgr.formatter = ln.JSONFormatter:new()
      lgr:log {foo = "bar"}
      assert.truthy(string.find(msg, "{"))
    end)
  end)

  describe("logfmt", function()
    local fmtr = ln.LogfmtFormatter:new()

    it("should return a non-nil message", function()
     assert.truthy(fmtr:format({foo = "bar"}))
    end)

    it("should have spaces when the input does", function()
      local msg = fmtr:format {foo = "bar with spaces"}
      assert.truthy(string.find(msg, 'foo="bar with spaces"'))
    end)
  end)

  describe("logger options", function()
    local msg
    local filter_func = function(message) msg = message end
    local lgr = ln.Logger:new {
      formatter = ln.LogfmtFormatter:new(),
      filters = {
        filter_func,
      }
    }
    
    it("sets the formatter to non-nil", function()
      assert.truthy(lgr.formatter)
    end)
    
    it("respects filters", function()
      lgr:log {foo = "bar"}
      assert.truthy(string.find(msg, 'foo=bar'))
    end)
    
    it("ends if a filter returns non-nil", function()
      msg = nil
      lgr.filters = {
        function(message) return false end,
        filter_func,
      }
      
      lgr:log {foo = "bar"}
      assert.falsy(msg)
    end)
  end)
end)