.env.example

@@ -2,5 +2,6 @@
 SMTP_ADDRESS="smtp.gmail.com"
 EMAIL_ADDRESS="you@example.com"
 EMAIL_PASSWORD="Use_an_App_Password_from_your_email_provider"
-# Optional: track another product instead of the default URL
+# Optional: the default is the Amazon product page. This value gives the
-# PRODUCT_URL="https://www.amazon.com/dp/B075CYMYK6"
+# practice page instead.
+# PRODUCT_URL="https://appbrewery.github.io/instant_pot/"

docs/artifact-registry.md

@@ -15,7 +15,7 @@ document of a type. `Primary File` may contain a glob (e.g.
 | SA | Stakeholder Analysis | docs/stakeholder-analysis.md | 002 |
 | PP | Project Plan | docs/project-plan.md | 002 |
 | MIL | Milestone / Gateway | docs/milestones/*.md | 007 |
-| RC | SQA Review Record | docs/sqa/reviews/rc-*.md | 014 |
+| RC | SQA Review Record | docs/sqa/reviews/rc-*.md | 015 |
 
 ## Languages
 

docs/sqa/reviews/rc-014-code-mil-005.md

@@ -0,0 +1,61 @@
+# RC-014 Code review of MIL-005
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | RC-014 |
+| CrossReference | [MIL-005], [QC-PY-001] |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| 2026-10-28 | Proposed | Jens Tirsvad Nielsen | AI as stand-in for S01 | Initial version | pending |
+
+---
+
+## Artifact Under Review
+
+- Instance reviewed: [MIL-005]
+- Checklist used: [QC-PY-001]
+- Scope: full review
+- Language and domain: n/a (technical)
+- Language reviewer: none
+- Mode: autonomous, not independent (AI as stand-in for S01); the author and the stand-in are both the AI working for S01
+
+## Checklist Results
+
+| # | Criterion | Status | Evidence/Notes |
+| --- | --- | --- | --- |
+| 1 | Packages, modules, functions, variables, classes and constants follow PEP 8 casing (`snake_case`, `PascalCase`, `UPPER_SNAKE`) | Pass | Modules and functions are snake_case, classes PascalCase, constants UPPER_SNAKE |
+| 2 | Names state purpose in the domain's language; no unexplained abbreviations, no single-letter names outside tiny scopes | Pass | Names state purpose (price, target, headers); no abbreviations left unexplained |
+| 3 | Code is produced by the project's formatter and passes its linter with no unexplained suppressions | Pass | ruff format and ruff check pass: 56 pytest tests (no network), ruff 0 findings, mypy strict 0 errors (26 files) |
+| 4 | Every function and method signature is type-annotated, including `-> None` | Pass | All signatures annotated; mypy --strict passes: 56 pytest tests (no network), ruff 0 findings, mypy strict 0 errors (26 files) |
+| 5 | No bare `except:`, no swallowed exceptions; specific exceptions are raised and the cause is kept (`raise ... from`) | Pass | No bare except; errors are specific and chained with `raise ... from` where a cause exists |
+| 6 | No mutable default arguments and no shadowed builtins | Pass | No mutable defaults, no shadowed builtins |
+| 7 | Files, locks and connections are managed with context managers | Pass | No open files or connections without a context manager |
+| 8 | Public modules, classes and functions have docstrings that say what, not how | Pass | Public modules and functions have docstrings with Doxygen tags |
+| 9 | Logging uses `logging`, not `print`; no secrets or personal data in log output | Pass | No secrets are logged; the invalid-setting error names the variable and never echoes the value; stderr messages only |
+| 10 | Classes and operations trace to the Design Class Diagram they implement; deviations are recorded | N-A | No Design Class Diagram exists; the milestone's technical tasks need none (Needs use case: No) |
+| 11 | Tests exist for new behaviour, are named for the behaviour, and do not depend on order or the network | Pass | Tests exist, are named for behaviour and use no network or real mail server: 56 pytest tests (no network), ruff 0 findings, mypy strict 0 errors (26 files) |
+| 12 | Type checker runs in strict mode without errors; `Any` is justified in a comment | Pass | mypy --strict passes; no Any |
+| 13 | Dependencies are declared and pinned in the project's dependency file, none unused | Pass | Dependencies are in pyproject.toml with lower bounds; none unused |
+| 14 | Each piece of knowledge (a business rule, constant, format, validation or query) is defined in one place; code is merged only where it expresses the same knowledge, not where it merely looks alike | Pass | Constants live only in constants.py |
+| 15 | Imports point inward: business-rule modules import no framework, database, UI or delivery-mechanism code, and there are no import cycles | Pass | Imports point inward; no cycles |
+| 16 | SOLID holds: a class or module has one reason to change; new behaviour is added by extension, not by editing a type test in several places; subclasses honour the contract of their base; protocols are narrow; high-level code depends on protocols or abstract types and receives its implementations | Pass | Selectors and markers are data in constants.py; detection is a separate function, so a new marker or selector is an extension, not an edit in several places |
+| 17 | Source is laid out in the layers and folders of the clean architecture folder structure (`domain`, `application`, `infrastructure`, `presentation` packages under `src/`, and `unit`, `integration` and `e2e` under `tests/`), in `snake_case`, and imports between the layers point inward | Pass | Layers and tests/unit/ mirror as before |
+| 18 | File and folder names are English, contain no space and no character outside letters, digits, `-`, `_` and `.`, and follow the casing of the language for files | Pass | File names are English snake_case |
+
+## Overall Verdict
+
+Go — all Mandatory criteria pass or are not applicable.
+
+## Action Items
+
+| Action | Owner | Due |
+| --- | --- | --- |
+| None: no Fail and no Pending criterion | S01 | 2026-10-28 |
+
+---
+
+[MIL-005]: ../../milestones/mil-005-live-amazon.md
+[QC-PY-001]: ../../../framework/qc/code/qc-programming-python.md

src/amazon_price_tracker/constants.py

@@ -49,6 +49,22 @@ DEFAULT_HEADERS: Final[Mapping[str, str]] = MappingProxyType(
     }
 )
 
+## @brief CSS selectors for the price, tried in order.
+# The first one skips decoy .a-offscreen spans (coupons) outside .a-price;
+# the second serves the practice page.
+PRICE_SELECTORS: Final[tuple[str, ...]] = (".a-price .a-offscreen", ".a-offscreen")
+
+## @brief CSS selectors for the product title, tried in order.
+TITLE_SELECTORS: Final[tuple[str, ...]] = ("#productTitle",)
+
+## @brief Text found only on Amazon's robot-check page.
+ROBOT_CHECK_MARKERS: Final[tuple[str, ...]] = (
+    "/errors_page/validateCaptcha",
+    "Click the button below to continue shopping",
+    "Enter the characters you see below",
+    "api-services-support@amazon.com",
+)
+
 ## @brief SMTP submission port (STARTTLS).
 SMTP_PORT: Final[int] = 587
 

src/amazon_price_tracker/domain/errors.py

@@ -17,5 +17,13 @@ class TitleNotFoundError(ProductParseError):
     """The page has no product title."""
 
 
+class RobotCheckError(ProductParseError):
+    """The page is a robot check, not a product page."""
+
+
 class MissingSettingError(Exception):
     """A required setting is missing or empty."""
+
+
+class InvalidSettingError(Exception):
+    """A setting has a value that is not allowed."""

src/amazon_price_tracker/infrastructure/scraper.py

@@ -4,40 +4,80 @@
 @brief Day 47 step 1: get the title and the price as a float.
 """
 
-from bs4 import BeautifulSoup
+from bs4 import BeautifulSoup, Tag
 
+from amazon_price_tracker.constants import (
+    PRICE_SELECTORS,
+    ROBOT_CHECK_MARKERS,
+    TITLE_SELECTORS,
+)
 from amazon_price_tracker.domain.errors import (
     PriceNotFoundError,
     ProductParseError,
+    RobotCheckError,
     TitleNotFoundError,
 )
 from amazon_price_tracker.domain.product import Product
 
 
+def is_robot_check(html: str) -> bool:
+    """Tell whether html is Amazon's robot-check page.
+
+    @param html Page HTML.
+    @return True when any robot-check marker is present.
+    """
+    return any(marker in html for marker in ROBOT_CHECK_MARKERS)
+
+
+def _ensure_not_robot_check(html: str) -> None:
+    if is_robot_check(html):
+        raise RobotCheckError(
+            "The page is a robot check, not a product page. "
+            "The bot does not try to get past it."
+        )
+
+
+def _select_first(html: str, selectors: tuple[str, ...]) -> Tag | None:
+    soup = BeautifulSoup(html, "html.parser")
+    for selector in selectors:
+        element = soup.select_one(selector)
+        if element is not None:
+            return element
+    return None
+
+
 def get_title(html: str) -> str:
-    """Return the text of the element with id productTitle, whitespace collapsed.
+    """Return the text of the product title element, whitespace collapsed.
 
     @param html Page HTML.
     @return The product title.
+    @throws RobotCheckError When the page is a robot check.
     @throws TitleNotFoundError When the element is missing.
     """
-    element = BeautifulSoup(html, "html.parser").select_one("#productTitle")
+    _ensure_not_robot_check(html)
+    element = _select_first(html, TITLE_SELECTORS)
     if element is None:
-        raise TitleNotFoundError("No element with id 'productTitle' on the page")
+        raise TitleNotFoundError(
+            f"No element matching {', '.join(TITLE_SELECTORS)} on the page"
+        )
     return " ".join(element.get_text().split())
 
 
 def get_price(html: str) -> float:
-    """Return the price of the first element with class a-offscreen.
+    """Return the price of the first element matching a price selector.
 
     @param html Page HTML.
     @return The price as a floating point number.
-    @throws PriceNotFoundError When the element is missing.
+    @throws RobotCheckError When the page is a robot check.
+    @throws PriceNotFoundError When no element matches.
     @throws ProductParseError When the price text is not a number.
     """
-    element = BeautifulSoup(html, "html.parser").select_one(".a-offscreen")
+    _ensure_not_robot_check(html)
+    element = _select_first(html, PRICE_SELECTORS)
     if element is None:
-        raise PriceNotFoundError("No element with class 'a-offscreen' on the page")
+        raise PriceNotFoundError(
+            f"No element matching {', '.join(PRICE_SELECTORS)} on the page"
+        )
     text = element.get_text().strip()
     # Text looks like "$99.99": drop the currency sign, as the hint suggests.
     amount = text.split("$")[-1].replace(",", "")
@@ -52,8 +92,10 @@ def parse_product(html: str) -> Product:
 
     @param html Page HTML.
     @return The product with title and price.
+    @throws RobotCheckError When the page is a robot check.
     @throws ProductParseError When the title or the price cannot be read.
     """
+    _ensure_not_robot_check(html)
     return Product(title=get_title(html), price=get_price(html))
 
 

src/amazon_price_tracker/infrastructure/settings.py

@@ -8,11 +8,13 @@ from collections.abc import Mapping
 from dataclasses import dataclass, field
 
 from amazon_price_tracker.constants import (
+    AMAZON_URL,
     ENV_EMAIL_ADDRESS,
     ENV_EMAIL_PASSWORD,
+    ENV_PRODUCT_URL,
     ENV_SMTP_ADDRESS,
 )
-from amazon_price_tracker.domain.errors import MissingSettingError
+from amazon_price_tracker.domain.errors import InvalidSettingError, MissingSettingError
 
 
 @dataclass(frozen=True, slots=True)
@@ -32,6 +34,22 @@ def _require(environ: Mapping[str, str], name: str) -> str:
     return value
 
 
+def load_product_url(environ: Mapping[str, str]) -> str:
+    """Return the product URL from environ, or the Amazon default.
+
+    @param environ Environment variables, for example os.environ.
+    @return The URL, stripped.
+    @throws InvalidSettingError When the value does not start with https://.
+    """
+    value = environ.get(ENV_PRODUCT_URL, "").strip()
+    if not value:
+        return AMAZON_URL
+    if not value.startswith("https://"):
+        # The value is not echoed: it may be long or carry a token.
+        raise InvalidSettingError(f"Invalid setting: {ENV_PRODUCT_URL} must be https")
+    return value
+
+
 def load_mail_settings(environ: Mapping[str, str]) -> MailSettings:
     """Return the mail settings found in environ.
 

src/amazon_price_tracker/main.py

@@ -10,12 +10,20 @@ import sys
 from dotenv import find_dotenv, load_dotenv
 
 from amazon_price_tracker.application.alert import check_price
-from amazon_price_tracker.constants import PRACTICE_URL, TARGET_PRICE
+from amazon_price_tracker.constants import TARGET_PRICE
-from amazon_price_tracker.domain.errors import MissingSettingError
+from amazon_price_tracker.domain.errors import (
+    InvalidSettingError,
+    MissingSettingError,
+    ProductParseError,
+    RobotCheckError,
+)
 from amazon_price_tracker.infrastructure.http_client import RequestsPageFetcher
 from amazon_price_tracker.infrastructure.mailer import SmtpNotifier
 from amazon_price_tracker.infrastructure.scraper import SoupProductParser
-from amazon_price_tracker.infrastructure.settings import load_mail_settings
+from amazon_price_tracker.infrastructure.settings import (
+    load_mail_settings,
+    load_product_url,
+)
 
 
 def main() -> None:
@@ -23,13 +31,26 @@ def main() -> None:
     load_dotenv(find_dotenv(usecwd=True))
     try:
         settings = load_mail_settings(os.environ)
-    except MissingSettingError as error:
+        url = load_product_url(os.environ)
+    except (MissingSettingError, InvalidSettingError) as error:
         print(f"{error}. Copy .env.example to .env and fill it in.", file=sys.stderr)
         return
     notifier = SmtpNotifier(settings)
+    try:
         result = check_price(
-        RequestsPageFetcher(), SoupProductParser(), notifier, PRACTICE_URL, TARGET_PRICE
+            RequestsPageFetcher(), SoupProductParser(), notifier, url, TARGET_PRICE
         )
+    except RobotCheckError:
+        print(
+            "Amazon returned a robot check page, so there is no price to read. "
+            "Try again later or set PRODUCT_URL to another page. "
+            "The bot does not try to get past the check.",
+            file=sys.stderr,
+        )
+        return
+    except ProductParseError as error:
+        print(f"Could not read the product: {error}", file=sys.stderr)
+        return
     print(result.product.title)
     print(result.product.price)
     print("Alert sent" if result.alert_sent else "Price is not below the target")

tests/fixtures/amazon_live_page.html

@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<!-- Synthetic example of live Amazon product markup: a coupon span with class a-offscreen comes before the real price, which sits in .a-price. -->
+<html lang="en-us">
+<head><title>Amazon.com: Instant Pot</title></head>
+<body>
+<span id="productTitle"> Instant Pot Duo 7-in-1 </span>
+<span class="a-size-base"><span class="a-offscreen">Save $5.00 with coupon</span></span>
+<span class="a-price a-text-price a-size-medium apexPriceToPay"><span class="a-offscreen">$79.95</span><span aria-hidden="true">$79.95</span></span>
+</body>
+</html>

tests/fixtures/amazon_robot_check.html

@@ -0,0 +1,82 @@
+<!DOCTYPE html>
+<!-- Robot-check page that www.amazon.com returned to the bot on 2026-10-28 (tokens redacted). -->
+<!--[if lt IE 7]> <html lang="en-us" class="a-no-js a-lt-ie9 a-lt-ie8 a-lt-ie7"> <![endif]-->
+<!--[if IE 7]>    <html lang="en-us" class="a-no-js a-lt-ie9 a-lt-ie8"> <![endif]-->
+<!--[if IE 8]>    <html lang="en-us" class="a-no-js a-lt-ie9"> <![endif]-->
+<!--[if gt IE 8]><!-->
+<html class="a-no-js" lang="en-us"><!--<![endif]--><head>
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+<meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
+<title dir="ltr">Amazon.com</title>
+<meta name="viewport" content="width=device-width">
+<link rel="stylesheet" href="https://images-na.ssl-images-amazon.com/images/G/01/AUIClients/AmazonUI-3c913031596ca78a3768f4e934b1cc02ce238101.secure.min._V1_.css">
+</head>
+<body>
+
+<!--
+        To discuss automated access to Amazon data please contact api-services-support@amazon.com.
+        For information about migrating to our APIs refer to our Marketplace APIs at https://developer.amazonservices.com/ref=rm_c_sv, or our Product Advertising API at https://affiliate-program.amazon.com/gp/advertising/api/detail/main.html/ref=rm_c_ac for advertising use cases.
+-->
+
+<!--
+Correios.DoNotSend
+-->
+
+<div class="a-container a-padding-double-large" style="min-width:350px;padding:44px 0 !important">
+
+    <div class="a-row a-spacing-double-large" style="width: 350px; margin: 0 auto">
+
+        <div class="a-row a-spacing-medium a-text-center"><i class="a-icon a-logo" alt="Amazon logo"></i></div>
+
+        <div class="a-box a-alert a-alert-info a-spacing-base">
+            <div class="a-box-inner">
+                <i class="a-icon a-icon-alert" alt="Alert icon"></i>
+                <h4>Click the button below to continue shopping</h4>
+                </div>
+            </div>
+
+            <div class="a-section">
+
+                <div class="a-box a-color-offset-background">
+                    <div class="a-box-inner a-padding-extra-large">
+
+                        <form method="get" action="/errors_page/validateCaptcha" name="">
+                            <input type="hidden" 
REDACTED" /><input type="hidden" name="amzn-r" value="&#047;" />
+                            <input type="hidden" 
REDACTED" />
+                            <div class="a-section a-spacing-extra-large">
+
+                                <div class="a-row">
+                                    <span class="a-button a-button-primary a-span12">
+                                        <span class="a-button-inner">
+                                            <button type="submit" class="a-button-text" alt="Continue shopping">Continue shopping</button>
+                                        </span>
+                                    </span>
+                                </div>
+
+                            </div>
+                        </form>
+
+                    </div>
+                </div>
+
+            </div>
+
+        </div>
+
+        <div class="a-divider a-divider-section"><div class="a-divider-inner"></div></div>
+
+        <div class="a-text-center a-spacing-small a-size-mini">
+            <a href="https://www.amazon.com/gp/help/customer/display.html/ref=footer_cou?ie=UTF8&nodeId=508088">Conditions of Use</a>
+            <span class="a-letter-space"></span>
+            <span class="a-letter-space"></span>
+            <span class="a-letter-space"></span>
+            <span class="a-letter-space"></span>
+            <a href="https://www.amazon.com/gp/help/customer/display.html/ref=footer_privacy?ie=UTF8&nodeId=468496">Privacy Policy</a>
+        </div>
+        <div class="a-text-center a-size-mini a-color-base">
+          &copy; 1996-2025, Amazon.com, Inc. or its affiliates
+        </div>
+    </div>
+</body></html>
+

tests/unit/infrastructure/test_scraper.py

@@ -5,6 +5,7 @@ import pytest
 from amazon_price_tracker.domain.errors import (
     PriceNotFoundError,
     ProductParseError,
+    RobotCheckError,
     TitleNotFoundError,
 )
 from amazon_price_tracker.domain.product import Product
@@ -12,6 +13,7 @@ from amazon_price_tracker.infrastructure.scraper import (
     SoupProductParser,
     get_price,
     get_title,
+    is_robot_check,
     parse_product,
 )
 
@@ -60,6 +62,42 @@ def test_parse_product_returns_product() -> None:
     assert product.price == 99.99
 
 
+def test_is_robot_check_true_for_robot_check_page() -> None:
+    assert is_robot_check(_read("amazon_robot_check.html"))
+
+
+@pytest.mark.parametrize("name", ["practice_page.html", "amazon_live_page.html"])
+def test_is_robot_check_false_for_product_page(name: str) -> None:
+    assert not is_robot_check(_read(name))
+
+
+def test_get_price_raises_robot_check_error_on_robot_check() -> None:
+    with pytest.raises(RobotCheckError):
+        get_price(_read("amazon_robot_check.html"))
+
+
+def test_get_title_raises_robot_check_error_on_robot_check() -> None:
+    with pytest.raises(RobotCheckError):
+        get_title(_read("amazon_robot_check.html"))
+
+
+def test_parse_product_raises_robot_check_error_on_robot_check() -> None:
+    with pytest.raises(RobotCheckError):
+        parse_product(_read("amazon_robot_check.html"))
+
+
+def test_robot_check_error_is_a_product_parse_error() -> None:
+    assert issubclass(RobotCheckError, ProductParseError)
+
+
+def test_get_price_skips_decoy_coupon_on_live_page() -> None:
+    assert get_price(_read("amazon_live_page.html")) == 79.95
+
+
+def test_get_title_strips_title_on_live_page() -> None:
+    assert get_title(_read("amazon_live_page.html")) == "Instant Pot Duo 7-in-1"
+
+
 def test_soup_product_parser_parses_html() -> None:
     product = SoupProductParser().parse(_read("practice_page.html"))
 

tests/unit/infrastructure/test_settings.py

@@ -1,12 +1,18 @@
 import pytest
 
 from amazon_price_tracker.constants import (
+    AMAZON_URL,
     ENV_EMAIL_ADDRESS,
     ENV_EMAIL_PASSWORD,
+    ENV_PRODUCT_URL,
     ENV_SMTP_ADDRESS,
+    PRACTICE_URL,
+)
+from amazon_price_tracker.domain.errors import InvalidSettingError, MissingSettingError
+from amazon_price_tracker.infrastructure.settings import (
+    load_mail_settings,
+    load_product_url,
 )
-from amazon_price_tracker.domain.errors import MissingSettingError
-from amazon_price_tracker.infrastructure.settings import load_mail_settings
 
 FULL = {
     ENV_SMTP_ADDRESS: "smtp.example.test",
@@ -43,6 +49,30 @@ def test_load_mail_settings_names_first_missing_variable() -> None:
         load_mail_settings({})
 
 
+def test_load_product_url_defaults_to_amazon() -> None:
+    assert load_product_url({}) == AMAZON_URL
+
+
+def test_load_product_url_defaults_when_blank() -> None:
+    assert load_product_url({ENV_PRODUCT_URL: "   "}) == AMAZON_URL
+
+
+def test_load_product_url_uses_override() -> None:
+    assert load_product_url({ENV_PRODUCT_URL: PRACTICE_URL}) == PRACTICE_URL
+
+
+def test_load_product_url_strips_whitespace() -> None:
+    assert load_product_url({ENV_PRODUCT_URL: f"  {PRACTICE_URL}\n"}) == PRACTICE_URL
+
+
+@pytest.mark.parametrize("value", ["http://example.test/", "ftp://x", "example.test"])
+def test_load_product_url_rejects_non_https(value: str) -> None:
+    with pytest.raises(InvalidSettingError, match=ENV_PRODUCT_URL) as info:
+        load_product_url({ENV_PRODUCT_URL: value})
+
+    assert value not in str(info.value)
+
+
 def test_mail_settings_repr_hides_password() -> None:
     assert "s3cret-pw" not in repr(load_mail_settings(FULL))
 

tests/unit/test_constants.py

@@ -42,6 +42,23 @@ def test_default_headers_are_non_empty() -> None:
     assert all(k.strip() and v.strip() for k, v in constants.DEFAULT_HEADERS.items())
 
 
+def test_selectors_and_markers_are_non_empty_tuples() -> None:
+    """Selectors and robot-check markers are non-empty tuples of text."""
+    for group in (
+        constants.PRICE_SELECTORS,
+        constants.TITLE_SELECTORS,
+        constants.ROBOT_CHECK_MARKERS,
+    ):
+        assert isinstance(group, tuple)
+        assert group
+        assert all(item.strip() for item in group)
+
+
+def test_price_selectors_try_specific_before_generic() -> None:
+    """The a-price selector comes before the bare a-offscreen one."""
+    assert constants.PRICE_SELECTORS == (".a-price .a-offscreen", ".a-offscreen")
+
+
 def test_smtp_port_is_starttls_port() -> None:
     """The SMTP port is 587."""
     assert constants.SMTP_PORT == 587