chore: increase unit test coverage, add some doctest

Author: milmazz

config/config.exs

@@ -15,7 +15,12 @@ defmodule CircularBuffer do
 
   defstruct [:a, :b, :max_size, :count]
   @typedoc "A circular buffer"
-  @opaque t() :: %__MODULE__{a: list(), b: list(), max_size: pos_integer(), count: non_neg_integer()}
+  @opaque t() :: %__MODULE__{
+            a: list(),
+            b: list(),
+            max_size: pos_integer(),
+            count: non_neg_integer()
+          }
 
   alias __MODULE__, as: CB
 
@@ -37,7 +42,7 @@ defmodule CircularBuffer do
 
   def insert(%CB{count: count, max_size: max_size} = cb, item) when count < max_size do
     %CB{cb | a: [item | cb.a], count: cb.count + 1}
-    end
+  end
 
   def insert(%CB{b: []} = cb, item) do
     new_b = cb.a |> Enum.reverse() |> tl()
@@ -55,6 +60,16 @@ defmodule CircularBuffer do
 
   @doc """
   Returns the newest element in the buffer
+
+  ## Examples
+
+      iex> cb = CircularBuffer.new(3)
+      iex> CircularBuffer.newest(cb)
+      nil
+      iex> cb = Enum.reduce(1..4, cb, fn n, cb -> CircularBuffer.insert(cb, n) end)
+      iex> CircularBuffer.newest(cb)
+      4
+
   """
   @spec newest(t()) :: any()
   def newest(%CB{a: [newest | _rest]}), do: newest
@@ -69,6 +84,17 @@ defmodule CircularBuffer do
 
   @doc """
   Checks the buffer to see if its empty
+
+  Returns `true` if the given circular buffer is empty, otherwise `false`.
+
+  ## Examples
+
+      iex> cb = CircularBuffer.new(1)
+      iex> CircularBuffer.empty?(cb)
+      true
+      iex> cb |> CircularBuffer.insert(1) |> CircularBuffer.empty?()
+      false
+
   """
   @spec empty?(t()) :: boolean()
   def empty?(%CB{} = cb) do

lib/circular_buffer.ex

@@ -1,7 +1,7 @@
 defmodule CircularBuffer.MixProject do
   use Mix.Project
 
-  @version "0.4.0"
+  @version "0.4.1-dev"
 
   def project do
     [

mix.exs

@@ -1,6 +1,7 @@
 defmodule CircularBufferTest do
   use ExUnit.Case, async: false
   use PropCheck
+  doctest CircularBuffer
 
   alias CircularBuffer, as: CB
 
@@ -39,6 +40,7 @@ defmodule CircularBufferTest do
 
   property "member?/1" do
     items = such_that({a, b} <- {pos_integer(), pos_integer()}, when: a != b)
+
     forall {a, b} <- items do
       cb = CB.new(1) |> CB.insert(a)
       !Enum.member?(cb, b) && Enum.member?(cb, a)
@@ -47,7 +49,7 @@ defmodule CircularBufferTest do
 
   property "implements Enumerable" do
     forall is <- list(integer()) do
-      buffer = Enum.reduce(is, CB.new(length(is)+1), fn i, cb -> CB.insert(cb, i) end)
+      buffer = Enum.reduce(is, CB.new(length(is) + 1), fn i, cb -> CB.insert(cb, i) end)
 
       Enum.reduce(buffer, 0, fn acc, i -> acc + i end) == Enum.sum(is)
     end
@@ -103,15 +105,15 @@ defmodule CircularBufferTest do
       oldest =
         iis
         |> Enum.reverse()
-        |> Enum.drop(size-1)
+        |> Enum.drop(size - 1)
         |> Enum.at(0)
 
       CB.oldest(buffer) == oldest
     end
   end
 
   test "can be inspected" do
-    str = inspect(Enum.into([1,2,3,4], CB.new(4)))
+    str = inspect(Enum.into([1, 2, 3, 4], CB.new(4)))
     assert str == "#CircularBuffer<[1, 2, 3, 4]>"
   end
 
@@ -148,16 +150,17 @@ defmodule CircularBufferTest do
 
   def size_and_list do
     let size <- pos_integer() do
-      let is <- ints(size*2, []) do
+      let is <- ints(size * 2 + 1, []) do
         {size, is}
       end
     end
   end
 
   defp ints(0, acc), do: acc
+
   defp ints(size, acc) do
     let i <- integer() do
-      ints(size-1, [i | acc])
+      ints(size - 1, [i | acc])
     end
   end
 end