fix: fix flaky test

2026-06-11 16:05:03 +02:00
parent 21b11ef87e
commit 284637970f
3 changed files with 124 additions and 4 deletions
--- a/lib/bds/generation/validation.ex
+++ b/lib/bds/generation/validation.ex
@@ -15,6 +15,11 @@ defmodule BDS.Generation.Validation do

  alias BDS.Slug

+  # POSIX mtimes from File.stat/2 have second granularity while generation
+  # timestamps are milliseconds, so ordering within one second is unknowable;
+  # only treat a source file as newer when it is beyond this tolerance.
+  @mtime_granularity_tolerance_ms 1_000
+
  @spec generated_file_updated_at_map([map()]) :: map()
  def generated_file_updated_at_map(generated_files) do
    Map.new(generated_files, &{&1.relative_path, &1.updated_at})
@@ -139,7 +144,8 @@ defmodule BDS.Generation.Validation do
                effective_generated_at_ms =
                  max(mtime_ms(html_stat), check.generated_updated_at_ms || 0)

-                if mtime_ms(post_stat) > effective_generated_at_ms do
+                if mtime_ms(post_stat) >
+                     effective_generated_at_ms + @mtime_granularity_tolerance_ms do
                  MapSet.put(acc, normalized_url_path)
                else
                  acc
--- a/test/bds/generation/validation_test.exs
+++ b/test/bds/generation/validation_test.exs
@@ -0,0 +1,97 @@
+defmodule BDS.Generation.ValidationTest do
+  use ExUnit.Case, async: true
+
+  alias BDS.Generation.Validation
+
+  @base_url "https://example.com/blog"
+  @post_url_path "/2026/06/01/sample-post"
+
+  setup do
+    temp_dir =
+      Path.join(System.tmp_dir!(), "bds-validation-#{System.unique_integer([:positive])}")
+
+    html_dir = Path.join(temp_dir, "html")
+    post_html_path = Path.join([html_dir, "2026", "06", "01", "sample-post", "index.html"])
+    source_path = Path.join(temp_dir, "sample-post.md")
+
+    File.mkdir_p!(Path.dirname(post_html_path))
+    File.write!(Path.join(html_dir, "index.html"), "<html>home</html>")
+    File.write!(post_html_path, "<html>post</html>")
+    File.write!(source_path, "Sample body")
+    on_exit(fn -> File.rm_rf(temp_dir) end)
+
+    %{html_dir: html_dir, post_html_path: post_html_path, source_path: source_path}
+  end
+
+  defp compare(html_dir, source_path, generated_updated_at_ms) do
+    sitemap_xml =
+      Enum.join([
+        ~s(<?xml version="1.0" encoding="UTF-8"?>),
+        ~s(<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">),
+        ~s(<url><loc>#{@base_url}/</loc></url>),
+        ~s(<url><loc>#{@base_url}#{@post_url_path}/</loc></url>),
+        ~s(</urlset>)
+      ])
+
+    Validation.compare_sitemap_to_html(%{
+      sitemap_xml: sitemap_xml,
+      base_url: @base_url,
+      html_dir: html_dir,
+      on_progress: nil,
+      post_timestamp_checks: [
+        %{
+          post_url_path: @post_url_path,
+          post_file_path: source_path,
+          generated_updated_at_ms: generated_updated_at_ms
+        }
+      ]
+    })
+  end
+
+  test "does not report a post as updated when its source mtime second adjoins the generation timestamp",
+       %{html_dir: html_dir, post_html_path: post_html_path, source_path: source_path} do
+    source_mtime = System.os_time(:second)
+
+    File.touch!(source_path, source_mtime)
+    File.touch!(post_html_path, source_mtime - 5)
+    File.touch!(Path.join(html_dir, "index.html"), source_mtime - 5)
+
+    generated_updated_at_ms = source_mtime * 1000 - 100
+
+    result = compare(html_dir, source_path, generated_updated_at_ms)
+
+    assert result.missing_url_paths == []
+    assert result.extra_url_paths == []
+    assert result.updated_post_url_paths == []
+  end
+
+  test "does not report a post as updated when its source mtime is in the same second as the generation timestamp",
+       %{html_dir: html_dir, post_html_path: post_html_path, source_path: source_path} do
+    source_mtime = System.os_time(:second)
+
+    File.touch!(source_path, source_mtime)
+    File.touch!(post_html_path, source_mtime - 5)
+    File.touch!(Path.join(html_dir, "index.html"), source_mtime - 5)
+
+    generated_updated_at_ms = source_mtime * 1000 + 500
+
+    result = compare(html_dir, source_path, generated_updated_at_ms)
+
+    assert result.updated_post_url_paths == []
+  end
+
+  test "reports a post as updated when its source mtime is beyond the granularity tolerance",
+       %{html_dir: html_dir, post_html_path: post_html_path, source_path: source_path} do
+    source_mtime = System.os_time(:second)
+
+    File.touch!(source_path, source_mtime)
+    File.touch!(post_html_path, source_mtime - 5)
+    File.touch!(Path.join(html_dir, "index.html"), source_mtime - 5)
+
+    generated_updated_at_ms = (source_mtime - 5) * 1000
+
+    result = compare(html_dir, source_path, generated_updated_at_ms)
+
+    assert result.updated_post_url_paths == [@post_url_path]
+  end
+end
--- a/test/bds/generation_test.exs
+++ b/test/bds/generation_test.exs
@@ -890,8 +890,8 @@ defmodule BDS.GenerationTest do
    source_path = Path.join([temp_dir, published_post.file_path])
    extra_path = Path.join([temp_dir, "html", "obsolete", "index.html"])

+    backdate_generated_outputs(project.id, temp_dir)
    File.rm!(post_file_path)
-    Process.sleep(1200)
    File.write!(source_path, File.read!(source_path) <> "\n")
    File.mkdir_p!(Path.dirname(extra_path))
    File.write!(extra_path, "<html>obsolete</html>")
@@ -973,12 +973,12 @@ defmodule BDS.GenerationTest do
    updated_post_source_path = Path.join([temp_dir, published_updated_post.file_path])
    extra_route_path = Path.join([temp_dir, "html", "obsolete", "deep", "index.html"])

+    backdate_generated_outputs(project.id, temp_dir)
    File.rm!(sitemap_path)
    File.rm!(missing_post_html_path)
    File.mkdir_p!(Path.dirname(extra_route_path))
    File.write!(extra_route_path, "<html>obsolete</html>")

-    Process.sleep(1200)
    File.write!(updated_post_source_path, File.read!(updated_post_source_path) <> "\n")

    assert {:ok, report} = BDS.Generation.validate_site(project.id)
@@ -1317,9 +1317,9 @@ defmodule BDS.GenerationTest do
    post_html_path = Path.join([temp_dir, "html", post_path])
    post_source_path = Path.join([temp_dir, published_post.file_path])

+    backdate_generated_outputs(project.id, temp_dir)
    before_stat = File.stat!(post_html_path)

-    Process.sleep(1200)
    File.write!(post_source_path, File.read!(post_source_path) <> "\n")

    assert {:ok, report} = BDS.Generation.validate_site(project.id)
@@ -1340,6 +1340,23 @@ defmodule BDS.GenerationTest do
    assert clean_report.updated_post_url_paths == []
  end

+  # Pushes generation timestamps and html mtimes far into the past so a
+  # subsequent source-file write is newer by more than the second-granularity
+  # mtime tolerance, without sleeping across real second boundaries.
+  defp backdate_generated_outputs(project_id, temp_dir) do
+    past_posix = System.os_time(:second) - 120
+
+    Repo.update_all(
+      from(g in BDS.Generation.GeneratedFileHash, where: g.project_id == ^project_id),
+      set: [updated_at: past_posix * 1000]
+    )
+
+    [temp_dir, "html", "**"]
+    |> Path.join()
+    |> Path.wildcard()
+    |> Enum.each(&File.touch!(&1, past_posix))
+  end
+
  defp relative_path_to_url_path(relative_path) do
    cleaned =
      relative_path