Stringify metrics in test client

[ChrisBr]

In our specs we use a test client to test if metrics were successfully written.

influxdb-rails/spec/support/test_client.rb

Lines 8 to 10 in 1c9d699

	def write_point(name, options = {})
	metrics << options.merge(name: name)
	end

The test client is basically just an array with hashes. To simplify our specs we also have a custom rspec matcher expect_metric.

influxdb-rails/spec/support/matchers.rb

Lines 7 to 17 in 1c9d699

	def expect_metric(name: "rails", **options)
	expect(metrics).to include(
	a_hash_including(options.merge(name: name))
	)
	end
	def expect_no_metric(name: "rails", **options)
	expect(metrics).not_to include(
	a_hash_including(options.merge(name: name))
	)
	end

The test client and matchers do distinguish between strings and symbols. For instance, in our implementation we set the default location to :raw and in our specs we need to assert also with a symbol.

# works
expect_metric(tags: a_hash_including(location: :raw))

# fails
expect_metric(tags: a_hash_including(location: "raw"))

I think this is a little bit surprising and caused me some time to debug. As InfluxDB only supports JSON anyway, I propose to just store string hashes in our test client and assert strings in our specs.