Simplify SensorWorker; support both with and without genserver

Author: mnishiguchi

README.md

@@ -19,8 +19,8 @@ Devices on I2C bus "i2c-1":
 1 devices detected on 1 I2C buses
 
 # Connect to the sensor.
-iex> {:ok, aht20} = AHT20.start(bus_name: "i2c-1", bus_address: 0x38)
-{:ok, AHT20.Sensor{}}
+iex> {:ok, aht20} = AHT20.start_link(bus_name: "i2c-1", bus_address: 0x38)
+{:ok, #PID<0.1407.0>}
 
 # Read the humidity and temperature from the sensor.
 iex> AHT20.read_data(aht20)
@@ -35,4 +35,4 @@ iex> AHT20.read_data(aht20)
 ```
 
 Depending on your hardware configuration, you may need to modify the call to
-`AHT20.start/1`. See `t:AHT20.Sensor.config/0` for parameters.
+`AHT20.start_link/1`. See `t:AHT20.Sensor.config/0` for parameters.

lib/aht20.ex

@@ -1,18 +1,37 @@
 defmodule AHT20 do
-  @moduledoc false
+  @moduledoc """
+  A collection of convenient functions to use this library.
+  """
+
+  @spec start(AHT20.Sensor.config()) :: {:ok, AHT20.Sensor.t()} | {:error, any}
+  def start(config) do
+    AHT20.Sensor.start(config)
+  end
 
   @spec start_link(AHT20.Sensor.config()) :: {:ok, pid} | {:error, any}
   def start_link(config) do
     AHT20.SensorWorker.start_link(config)
   end
 
-  @spec read_data() :: {:ok, AHT20.Measurement.t()} | {:error, any}
-  def read_data() do
-    AHT20.SensorWorker.read_data()
+  @spec read_data(pid) :: {:ok, AHT20.Measurement.t()} | {:error, any}
+  def read_data(pid) when is_pid(pid) do
+    AHT20.SensorWorker.read_data(pid)
+  end
+
+  @spec read_data(AHT20.Sensor.t()) :: {:ok, AHT20.Measurement.t()} | {:error, any}
+  def read_data(%AHT20.Sensor{} = sensor) when is_struct(sensor) do
+    {:ok, sensor_output} = AHT20.Sensor.read_data(sensor)
+    {:ok, AHT20.Measurement.from_sensor_output(sensor_output)}
+  end
+
+  @spec read_state(pid) :: {:ok, AHT20.State.t()} | {:error, any}
+  def read_state(pid) when is_pid(pid) do
+    AHT20.SensorWorker.read_state(pid)
   end
 
-  @spec read_state() :: {:ok, AHT20.State.t()} | {:error, any}
-  def read_state() do
-    AHT20.SensorWorker.read_state()
+  @spec read_state(AHT20.Sensor.t()) :: {:ok, AHT20.State.t()} | {:error, any}
+  def read_state(%AHT20.Sensor{} = sensor) when is_struct(sensor) do
+    {:ok, <<sensor_state_byte>>} = AHT20.Sensor.read_state(sensor)
+    {:ok, AHT20.State.from_byte(sensor_state_byte)}
   end
 end

lib/aht20/sensor_worker.ex

@@ -9,12 +9,12 @@ defmodule AHT20.SensorWorker do
 
   @spec start_link(AHT20.Sensor.config()) :: {:ok, pid} | {:error, any}
   def start_link(config) do
-    GenServer.start_link(__MODULE__, config, name: __MODULE__)
+    GenServer.start_link(__MODULE__, config)
   end
 
-  def read_data, do: GenServer.call(__MODULE__, :read_data)
+  def read_data(pid), do: GenServer.call(pid, :read_data)
 
-  def read_state, do: GenServer.call(__MODULE__, :read_state)
+  def read_state(pid), do: GenServer.call(pid, :read_state)
 
   @impl GenServer
   def init(config) do

test/aht20_test.exs

@@ -15,33 +15,67 @@ defmodule AHT20Test do
     :ok
   end
 
-  test "start_link" do
-    config = [i2c_bus: "i2c-1", i2c_address: 0x38]
-    assert {:ok, _} = AHT20.start_link(config)
-  end
+  describe "without worker" do
+    test "start" do
+      config = [i2c_bus: "i2c-1", i2c_address: 0x38]
+      assert {:ok, _} = AHT20.start(config)
+    end
+
+    test "read_data" do
+      AHT20.MockI2C
+      |> Mox.expect(:read, 1, fn _ref, _address, _data, [] -> {:ok, <<28, 38, 154, 118, 66, 231, 118>>} end)
 
-  test "read_data" do
-    AHT20.MockI2C
-    |> Mox.expect(:read, 1, fn _ref, _address, _data, [] -> {:ok, <<28, 38, 154, 118, 66, 231, 118>>} end)
+      sensor = %AHT20.Sensor{i2c_address: 0x38, i2c_bus: "i2c-1", i2c_ref: make_ref()}
+      assert {:ok, data} = AHT20.read_data(sensor)
 
-    assert {:ok, _pid} = AHT20.start_link(i2c_bus: "i2c-1", i2c_address: 0x38)
-    assert {:ok, data} = AHT20.read_data()
+      assert data == %AHT20.Measurement{
+               raw_humidity: 158_119,
+               raw_temperature: 410_343,
+               relative_humidity: 15.079402923583984,
+               temperature_c: 28.26671600341797,
+               temperature_f: 82.88008880615234
+             }
+    end
 
-    assert data == %AHT20.Measurement{
-             raw_humidity: 158_119,
-             raw_temperature: 410_343,
-             relative_humidity: 15.079402923583984,
-             temperature_c: 28.26671600341797,
-             temperature_f: 82.88008880615234
-           }
+    test "read_state" do
+      AHT20.MockI2C
+      |> Mox.expect(:write_read, 1, fn _ref, _address, _data, _bytes_to_read, [] -> {:ok, <<0b00011100>>} end)
+
+      sensor = %AHT20.Sensor{i2c_address: 0x38, i2c_bus: "i2c-1", i2c_ref: make_ref()}
+      assert {:ok, state} = AHT20.read_state(sensor)
+      assert state == %AHT20.State{busy: false, calibrated: true, mode: :nor}
+    end
   end
 
-  test "read_state" do
-    AHT20.MockI2C
-    |> Mox.expect(:write_read, 1, fn _ref, _address, _data, _bytes_to_read, [] -> {:ok, <<0b00011100>>} end)
+  describe "with worker" do
+    test "start_link" do
+      config = [i2c_bus: "i2c-1", i2c_address: 0x38]
+      assert {:ok, _} = AHT20.start_link(config)
+    end
+
+    test "read_data" do
+      AHT20.MockI2C
+      |> Mox.expect(:read, 1, fn _ref, _address, _data, [] -> {:ok, <<28, 38, 154, 118, 66, 231, 118>>} end)
+
+      assert {:ok, pid} = AHT20.start_link(i2c_bus: "i2c-1", i2c_address: 0x38)
+      assert {:ok, data} = AHT20.read_data(pid)
+
+      assert data == %AHT20.Measurement{
+               raw_humidity: 158_119,
+               raw_temperature: 410_343,
+               relative_humidity: 15.079402923583984,
+               temperature_c: 28.26671600341797,
+               temperature_f: 82.88008880615234
+             }
+    end
+
+    test "read_state" do
+      AHT20.MockI2C
+      |> Mox.expect(:write_read, 1, fn _ref, _address, _data, _bytes_to_read, [] -> {:ok, <<0b00011100>>} end)
 
-    AHT20.start_link(i2c_bus: "i2c-1", i2c_address: 0x38)
-    assert {:ok, state} = AHT20.read_state()
-    assert state == %AHT20.State{busy: false, calibrated: true, mode: :nor}
+      assert {:ok, pid} = AHT20.start_link(i2c_bus: "i2c-1", i2c_address: 0x38)
+      assert {:ok, state} = AHT20.read_state(pid)
+      assert state == %AHT20.State{busy: false, calibrated: true, mode: :nor}
+    end
   end
 end