bikoret/vav_pipeline/test/no_tracking_logger_test.exs

defmodule VavPipeline.NoTrackingLoggerTest do
  @moduledoc """
  Tests for the Plug-layer enforcement of Form 3.

  Verifies:
    - The router uses NoTrackingLogger, not Plug.Logger
    - /peah/* paths get sanitized (query strings dropped) in logs
    - Each request increments MachtzitHaShekel
    - CI invariants: no Plug.Session, no Plug.Conn.Cookies imports
      anywhere in the source tree
  """

  use ExUnit.Case, async: false

  import Plug.Test

  alias VavPipeline.{BigdeiKodesh.Router, MachtzitHaShekel, NoTrackingLogger}

  @opts Router.init([])

  setup do
    if Process.whereis(MachtzitHaShekel), do: MachtzitHaShekel.reset()
    :ok
  end

  # ============================================================
  # Each request increments the zikaron
  # ============================================================

  test "GET /peah/ask increments the half-shekel count" do
    before_count = if Process.whereis(MachtzitHaShekel), do: MachtzitHaShekel.count(), else: 0

    conn(:get, "/peah/ask") |> Router.call(@opts)

    after_count = if Process.whereis(MachtzitHaShekel), do: MachtzitHaShekel.count(), else: 0
    assert after_count == before_count + 1
  end

  test "multiple requests advance the count uniformly" do
    if Process.whereis(MachtzitHaShekel) do
      MachtzitHaShekel.reset()

      for _ <- 1..5 do
        conn(:get, "/peah/ask") |> Router.call(@opts)
      end

      assert MachtzitHaShekel.count() == 5
    else
      flunk("MachtzitHaShekel not running — supervision tree must be up for this test")
    end
  end

  # ============================================================
  # PRIVACY BOUNDARY — sanitized_path/1 and format_line/2 as pure functions
  # ============================================================
  # The test config sets logger level to :warning, dropping
  # NoTrackingLogger's :info output before capture_log can see it.
  # The structural defense is the load-bearing thing; we test the
  # pure functions directly to verify the path-sanitization shape.

  test "sanitized_path drops query string on /peah/*" do
    conn = %Plug.Conn{request_path: "/peah/ask", query_string: "question=secret"}
    assert NoTrackingLogger.sanitized_path(conn) == "/peah/ask"
  end

  test "sanitized_path drops the question parameter on /peah/ask" do
    secret = "this-question-must-not-leak"
    conn = %Plug.Conn{request_path: "/peah/ask", query_string: "question=#{secret}"}
    sanitized = NoTrackingLogger.sanitized_path(conn)
    refute sanitized =~ secret
    refute sanitized =~ "question"
    refute sanitized =~ "?"
  end

  test "sanitized_path preserves path class for /peah/azazel_log" do
    conn = %Plug.Conn{request_path: "/peah/azazel_log", query_string: "since=2026-01-01"}
    assert NoTrackingLogger.sanitized_path(conn) == "/peah/azazel_log"
  end

  test "sanitized_path preserves request_path on non-peah tiers" do
    # Non-peah tiers also strip query string (the request_path itself
    # doesn't carry it; query is in conn.query_string).
    conn = %Plug.Conn{request_path: "/kodesh/health", query_string: "detail=full"}
    assert NoTrackingLogger.sanitized_path(conn) == "/kodesh/health"
  end

  test "format_line shape: METHOD PATH STATUS DURATIONus" do
    conn = %Plug.Conn{
      method: "GET",
      request_path: "/peah/ask",
      query_string: "question=secret",
      status: 200
    }

    line = NoTrackingLogger.format_line(conn, 1234)
    assert line == "GET /peah/ask 200 1234us"
  end

  test "format_line never contains a query string for /peah/*" do
    secret = "secret-question-content"

    conn = %Plug.Conn{
      method: "GET",
      request_path: "/peah/ask",
      query_string: "question=#{secret}",
      status: 200
    }

    line = NoTrackingLogger.format_line(conn, 100)
    refute line =~ secret
  end

  test "format_line never contains an Authorization header" do
    # The format_line function takes only conn and duration. It does
    # NOT extract headers. Verifying by inspection: the function
    # signature gives no path for headers to enter the log.
    bearer = "secret-bearer-token"

    conn = %Plug.Conn{
      method: "POST",
      request_path: "/courtyard/offering",
      query_string: "",
      status: 200,
      req_headers: [{"authorization", "Bearer #{bearer}"}]
    }

    line = NoTrackingLogger.format_line(conn, 100)
    refute line =~ bearer
    refute line =~ "Bearer"
    refute line =~ "authorization"
  end

  test "format_line never contains conn.remote_ip even when set" do
    conn = %Plug.Conn{
      method: "GET",
      request_path: "/peah/ask",
      query_string: "",
      status: 200,
      remote_ip: {192, 0, 2, 1}
    }

    line = NoTrackingLogger.format_line(conn, 100)
    refute line =~ "192.0.2.1"
    refute line =~ "192"
  end

  # ============================================================
  # CI INVARIANTS — Form 3 architectural enforcement
  # ============================================================
  # These tests walk the source tree and verify no module introduces
  # a surveillance surface that would defeat the architectural
  # commitment.

  @vav_pipeline_lib "lib/vav_pipeline"

  # NoTrackingLogger's own docstring mentions the forbidden module
  # names as the things it defends against. Exclude the defender file
  # from the CI scan to avoid self-detection. Tests are also excluded
  # — they can legitimately reference the names in assertions.
  @ci_invariant_exclusions [
    "lib/vav_pipeline/no_tracking_logger.ex"
  ]

  defp source_files do
    Path.wildcard("#{@vav_pipeline_lib}/**/*.ex")
    |> Enum.reject(fn path -> path in @ci_invariant_exclusions end)
  end

  test "Plug.Logger is NOT mounted in any router" do
    offenders =
      Enum.filter(source_files(), fn path ->
        text = File.read!(path)
        String.contains?(text, "plug Plug.Logger")
      end)

    assert offenders == [], (
      "Plug.Logger is mounted in: #{inspect(offenders)}. The Form 3 " <>
        "architectural commitment requires NoTrackingLogger as the " <>
        "request-scoped logger; Plug.Logger logs unconfigurable details " <>
        "(method+path+status+timing) without the path sanitization that " <>
        "honors /peah/*'s no-tracking promise."
    )
  end

  test "no module imports Plug.Session" do
    offenders =
      Enum.filter(source_files(), fn path ->
        text = File.read!(path)

        String.contains?(text, "Plug.Session") and
          not String.contains?(text, "no module imports Plug.Session")
      end)

    assert offenders == [], (
      "Plug.Session is imported in: #{inspect(offenders)}. Sessions " <>
        "are per-caller persistent state — exactly the surveillance " <>
        "surface Form 3 forbids. The system is stateless per-request " <>
        "by architectural commitment."
    )
  end

  test "no module imports Plug.Conn.Cookies" do
    offenders =
      Enum.filter(source_files(), fn path ->
        text = File.read!(path)

        String.contains?(text, "Plug.Conn.Cookies") and
          not String.contains?(text, "no module imports Plug.Conn.Cookies")
      end)

    assert offenders == [], (
      "Plug.Conn.Cookies imported in: #{inspect(offenders)}. Cookies " <>
        "are per-caller persistent state — Form 3 surveillance " <>
        "surface. The system is cookie-free by architectural " <>
        "commitment."
    )
  end

  test "no module reads remote IP from conn.remote_ip" do
    # remote_ip captures the caller's IP — a per-caller identifier.
    offenders =
      Enum.filter(source_files(), fn path ->
        text = File.read!(path)

        String.contains?(text, "conn.remote_ip") and
          not String.contains?(text, "no module reads remote IP")
      end)

    assert offenders == [], (
      "Modules reading conn.remote_ip: #{inspect(offenders)}. The IP " <>
        "is a caller identifier; persisting it would defeat the " <>
        "kofer-nefesh anonymity (Shemot 30:13) and the lo-tasgir " <>
        "refusal (Devarim 23:16)."
    )
  end
end