Make System a struct

Adding fields was painful before and I missed where I should add
them, this should make it easier to have the compiler check it
for you.

CHANGELOG.md

@@ -11,7 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * System information now includes whether or not the JIT is enabled ([erlang docs](https://www.erlang.org/doc/apps/erts/beamasm)).
 
 ### Features (Plugins)
-* `jit_enabled?` is exposed as part of the `suite.system` map
+* `jit_enabled?` is exposed as part of the `suite.system` struct
+* Yes, `Benchee.System` is now a struct so feel easier about relying on the fields
 
 ## 1.2.0 (2023-11-09)
 

lib/benchee/output/benchmark_printer.ex

@@ -1,7 +1,7 @@
 defmodule Benchee.Output.BenchmarkPrinter do
   @moduledoc false
 
-  alias Benchee.{Benchmark, Conversion.Duration}
+  alias Benchee.{Benchmark, Conversion.Duration, System}
 
   @doc """
   Shown when you try benchmark an evaluated function.
@@ -41,7 +41,7 @@ defmodule Benchee.Output.BenchmarkPrinter do
     suite_information(scenarios, config)
   end
 
-  defp system_information(%{
+  defp system_information(%System{
          erlang: erlang_version,
          elixir: elixir_version,
          jit_enabled?: jit_enabled?,

lib/benchee/suite.ex

@@ -27,7 +27,7 @@ defmodule Benchee.Suite do
   """
   @type t :: %__MODULE__{
           configuration: Benchee.Configuration.t() | nil,
-          system: map | nil,
+          system: Benchee.System.t() | nil,
           scenarios: [] | [Benchee.Scenario.t()]
         }
 end

lib/benchee/system.ex

@@ -11,14 +11,44 @@ defmodule Benchee.System do
   alias Benchee.Suite
   alias Benchee.Utility.ErlangVersion
 
+  @enforce_keys [
+    :elixir,
+    :erlang,
+    :jit_enabled?,
+    :num_cores,
+    :os,
+    :available_memory,
+    :cpu_speed
+  ]
+
+  defstruct [
+    :elixir,
+    :erlang,
+    :jit_enabled?,
+    :num_cores,
+    :os,
+    :available_memory,
+    :cpu_speed
+  ]
+
+  @type t :: %__MODULE__{
+          elixir: String.t(),
+          erlang: String.t(),
+          jit_enabled?: boolean(),
+          num_cores: pos_integer(),
+          os: :macOS | :Windows | :FreeBSD | :Linux,
+          cpu_speed: String.t(),
+          available_memory: String.t()
+        }
+
   @doc """
   Adds system information to the suite (currently elixir and erlang versions).
   """
   @spec system(Suite.t()) :: Suite.t()
   def system(suite = %Suite{}) do
     erlang_version = erlang()
 
-    system_info = %{
+    system_info = %__MODULE__{
       elixir: elixir(),
       erlang: erlang_version,
       jit_enabled?: jit_enabled?(erlang_version),
@@ -217,3 +247,13 @@ defmodule Benchee.System do
     end
   end
 end
+
+defimpl DeepMerge.Resolver, for: Benchee.System do
+  def resolve(original, override = %Benchee.System{}, resolver) do
+    Map.merge(original, override, resolver)
+  end
+
+  def resolve(original, override, resolver) when is_map(override) do
+    Map.merge(original, override, resolver)
+  end
+end

test/benchee/benchmark/runner_test.exs

@@ -4,7 +4,7 @@ defmodule Benchee.Benchmark.RunnerTest do
   import Benchee.TestHelpers
   import ExUnit.CaptureIO
 
-  alias Benchee.{Benchmark, Configuration, Scenario, Suite}
+  alias Benchee.{Benchmark, Configuration, Scenario, Suite, System}
   alias Benchee.Test.FakeBenchmarkPrinter, as: TestPrinter
 
   @config %Configuration{
@@ -16,7 +16,7 @@ defmodule Benchee.Benchmark.RunnerTest do
     print: %{fast_warning: false, configuration: true},
     measure_function_call_overhead: false
   }
-  @system %{
+  @system %System{
     elixir: "1.4.0",
     erlang: "19.1",
     jit_enabled?: false,

test/benchee/output/benchmark_printer_test.exs

@@ -1,12 +1,12 @@
 defmodule Benchee.Output.BenchmarkPrintertest do
   use ExUnit.Case, async: true
 
-  alias Benchee.{Benchmark, Configuration, Scenario}
+  alias Benchee.{Benchmark, Configuration, Scenario, System}
 
   import ExUnit.CaptureIO
   import Benchee.Output.BenchmarkPrinter
 
-  @system_info %{
+  @system_info %System{
     elixir: "1.15.7",
     erlang: "26.1",
     jit_enabled?: true,

test/benchee/suite_test.exs

@@ -1,11 +1,22 @@
 defmodule Benchee.SuiteTest do
   use ExUnit.Case, async: true
 
-  alias Benchee.Suite
   import DeepMerge
 
+  alias Benchee.Suite
+  alias Benchee.System
+
+  @system %System{
+    elixir: "1.4.0",
+    erlang: "19.2",
+    jit_enabled?: false,
+    num_cores: "4",
+    os: "Super Duper",
+    available_memory: "8 Trillion",
+    cpu_speed: "light speed"
+  }
   @empty_suite %Suite{
-    system: %{elixir: "1.4.2", erlang: "19.2"},
+    system: @system,
     scenarios: []
   }
 
@@ -46,7 +57,7 @@ defmodule Benchee.SuiteTest do
   if Code.ensure_loaded?(Table.Reader) do
     describe "Table.Reader protocol" do
       @suite_with_data %Suite{
-        system: %{elixir: "1.4.2", erlang: "19.2"},
+        system: @system,
         configuration: %Benchee.Configuration{
           percentiles: [50, 99]
         },
@@ -147,7 +158,7 @@ defmodule Benchee.SuiteTest do
       }
 
       @suite_with_reductions %Suite{
-        system: %{elixir: "1.14.2", erlang: "25.2"},
+        system: @system,
         configuration: %Benchee.Configuration{
           percentiles: [50, 99]
         },

test/benchee/system_test.exs

@@ -5,6 +5,7 @@ defmodule Benchee.SystemTest do
   import Benchee.System
 
   alias Benchee.Suite
+  alias Benchee.System
   alias Benchee.Utility.ErlangVersion
 
   test ".system adds the content to a given suite" do
@@ -136,4 +137,20 @@ defmodule Benchee.SystemTest do
       refute jit_enabled?
     end
   end
+
+  @system %System{
+    elixir: "1.4.0",
+    erlang: "19.1",
+    jit_enabled?: false,
+    num_cores: "4",
+    os: "Super Duper",
+    available_memory: "8 Trillion",
+    cpu_speed: "light speed"
+  }
+  describe "deep_merge behaviour" do
+    test "it merges with a map preserving other keys" do
+      assert %{elixir: "1.15.7", erlang: "19.1"} =
+               DeepMerge.deep_merge(@system, %{elixir: "1.15.7"})
+    end
+  end
 end