[codex] Add refactor coverage

[DTTerastar]

Summary

• Extract pure JSON and endpoint helper logic into an internal header used by production code.
• Expand native tests to cover string/numeric JSON rendering, password masking, int/float/bool conversions, and /wifi endpoint alias resolution.
• Clarify README credential registration required for provisioning through the generic /wifi endpoint.

Validation

• pio test -e native

Summary by CodeRabbit

• Documentation

  • Added guidance for configuring WiFi credentials through the /wifi endpoint.
  • Clarified credential persistence and how saved values are used to connect.

• Bug Fixes

  • Improved JSON formatting for strings, numbers, passwords, and boolean values.
  • Improved WiFi endpoint and request-path handling.

• Tests

  • Expanded coverage for JSON encoding, password masking, value parsing, and WiFi endpoint resolution.

[coderabbitai]

Walkthrough

The change extracts JSON and WiFi endpoint helpers into a new internal header, updates HeadlessWiFiSettings to use them, expands test stubs and coverage, and documents WiFi credential registration and SPIFFS paths.

Changes

WiFi helper refactor

Layer / File(s)	Summary
Shared JSON and endpoint helpers src/HeadlessWiFiSettingsInternals.h	Adds reusable JSON formatting, password masking, endpoint parsing, and endpoint lookup helpers.
Settings implementation integration src/HeadlessWiFiSettings.cpp, README.md	Uses the shared helpers for parameter serialization and /wifi path handling, and documents WiFi credential registration and storage paths.
Helper test support and coverage test/stubs/Arduino.h, test/test_json_encode/test_main.cpp	Extends the Arduino String stub and adds tests for JSON encoding, password handling, numeric and boolean values, and endpoint utilities.

Possibly related PRs

• ESPresense/HeadlessWiFiSettings#2: Refactors JSON encoding through a separate utility header in overlapping code paths.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title is related to the PR’s main theme: adding test coverage for a refactor.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/add-refactor-coverage

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@README.md`:
- Around line 81-90: Update the earlier minimal connect() example in README.md
to register both “wifi-ssid” and “wifi-password” with HeadlessWiFiSettings
before calling connect(). Keep the existing portal flow unchanged and match the
registrations shown in the generic /wifi configuration example.

In `@test/stubs/Arduino.h`:
- Line 18: Update the float constructor in String to format values with
fixed-point precision of two decimal places, matching ESP32 Arduino output. In
test/stubs/Arduino.h lines 18-18, replace the default std::to_string formatting;
in test/test_json_encode/test_main.cpp lines 55-58, update the float JSON
expectations to `"interval":2.50` and `"interval":0.00`.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 1d956c3e-9e3f-424c-bcc2-23f39aac460b

📥 Commits

Reviewing files that changed from the base of the PR and between 1831b2c and 565aca1.

📒 Files selected for processing (5)

• README.md
• src/HeadlessWiFiSettings.cpp
• src/HeadlessWiFiSettingsInternals.h
• test/stubs/Arduino.h
• test/test_json_encode/test_main.cpp

[coderabbitai]

🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win

Update the minimal provisioning example too.

The earlier connect() example omits these required registrations, so its portal flow cannot configure credentials through generic /wifi. Add the same two registrations before connect() there.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@README.md` around lines 81 - 90, Update the earlier minimal connect() example
in README.md to register both “wifi-ssid” and “wifi-password” with
HeadlessWiFiSettings before calling connect(). Keep the existing portal flow
unchanged and match the registrations shown in the generic /wifi configuration
example.

[coderabbitai]

🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
set -euo pipefail

echo "== candidate files =="
git ls-files | rg 'test/stubs/Arduino.h|test/test_json_encode/test_main.cpp|jsonFloat|Arduino.h' || true

echo
echo "== relevant file excerpts =="
for f in test/stubs/Arduino.h test/test_json_encode/test_main.cpp; do
  if [ -f "$f" ]; then
    echo "--- $f"
    nl -ba "$f" | sed -n '1,90p'
  fi
done

echo
echo "== search for jsonFloat and String(float) usages =="
rg -n 'jsonFloat|String\(float|string\(float|to_string' . --glob '!build/**' --glob '!dist/**' || true

echo
echo "== C++ locale/stdlib behavioral probe for default std::to_string(2.5) =="
python3 - <<'PY'
print("Python can only show locale/config info, not compile/use std::to_string here.")
PY

Repository: ESPresense/HeadlessWiFiSettings

Length of output: 344

---

🌐 Web query:

ESP32 Arduino WString String(float) default decimal places 2

💡 Result:

The ESP32 Arduino String constructor for floating-point numbers has a default of 2 decimal places [1][2]. Specifically, the constructor is defined as: String(float value, unsigned int decimalPlaces = 2); [1][2] When you initialize a String with a float (or double) without specifying the precision, the String class automatically uses this default value of 2 [1][3]. You can override this by providing the desired number of decimal places as the second argument, for example: String myString = String(12.3456, 3); which would result in "12.346" [4][3]. Under the hood, the ESP32 Arduino core implements this using dtostrf [5][6]. Note that while you can specify the number of decimal places, you should be mindful of the physical limitations of the float data type (which typically provides about 6-7 significant digits of precision) and avoid extremely large values for decimalPlaces to prevent potential memory or buffer issues [7][8].

Citations:

• 1: https://github.com/espressif/arduino-esp32/blob/7a82915de215ec0572e0d3e10fb44674056ec885/cores/esp32/WString.h
• 2: https://github.com/espressif/arduino-esp32/blob/cf448906b3836fbe9368934713b697469254c62f/cores/esp32/WString.h
• 3: https://www.arduino.cc/reference/cs/language/variables/data-types/stringobject/
• 4: https://forum.arduino.cc/t/how-to-add-more-digits-after-decimal-point-with-print-and-string-command/1221516/1
• 5: https://github.com/espressif/arduino-esp32/blob/3.1.3/cores/esp32/WString.cpp
• 6: https://github.com/espressif/arduino-esp32/blob/3.0.7/cores/esp32/WString.cpp
• 7: Stack smash with String(float, precision) espressif/arduino-esp32#5873
• 8: https://forum.arduino.cc/t/string-constructor-doesnt-convert-float-type-correctly/408137/4

---

🏁 Script executed:

#!/bin/bash
set -euo pipefail

echo "== relevant file excerpts =="
for f in test/stubs/Arduino.h test/test_json_encode/test_main.cpp; do
  if [ -f "$f" ]; then
    echo "--- $f"
    awk '{printf "%5d\t%s\n", NR, $0}' "$f" | sed -n '1,120p'
  fi
done

echo
echo "== targeted search for jsonFloat and float string conversions =="
if command -v rg >/dev/null 2>&1; then
  rg -n 'jsonFloat|String\(float|string\(float|to_string' . --glob '!build/**' --glob '!dist/**' || true
else
  grep -RInE 'jsonFloat|String\(float|string\(float|to_string' . --exclude-dir=build --exclude-dir=dist || true
fi

Repository: ESPresense/HeadlessWiFiSettings

Length of output: 10214

---

🌐 Web query:

C++ default locale std::to_string(2.5) std::to_string(0.0)

💡 Result:

The behavior of std::to_string(2.5) and std::to_string(0.0) depends on the C++ standard version used, as the specification for floating-point conversions changed significantly in C++26 [1]. For C++11 through C++23: std::to_string is defined to produce the same result as std::sprintf with a format specifier of "%f" [2][1]. This means: - The output is affected by the current C locale [3][4][5]. If the locale uses a comma as the decimal separator (e.g., in many European locales), std::to_string will output "2,5" and "0,000000" instead of "2.5" and "0.000000" [6][7][5]. - The default precision for "%f" is 6 decimal places [6]. - std::to_string(2.5) typically results in "2.500000" (or the localized equivalent) [6]. - std::to_string(0.0) typically results in "0.000000" (or the localized equivalent) [6][1]. For C++26 and later: The standard was updated to define std::to_string in terms of std::format, which is locale-independent [8][1]. - The output no longer depends on the current C locale [8]. - The decimal separator will always be a dot ('.') [8]. - It uses the shortest decimal representation rather than a fixed precision, typically resulting in "2.5" for 2.5 and "0.0" for 0.0 (exact details depend on the implementation of std::format's floating-point formatting) [8][1]. To ensure locale-independent, consistent behavior across all C++ versions, it is recommended to avoid std::to_string for floating-point values when the output format must be predictable (e.g., for serialization, logs, or protocol data) [8][7][5]. Alternatives include std::to_chars (since C++17) or std::format (since C++20), which are locale-independent [3][8][5].

Citations:

• 1: https://cppreference.com/cpp/string/basic_string/to_string
• 2: https://timsong-cpp.github.io/cppwp/std11/string.conversions
• 3: https://en.cppreference.com/cpp/string/basic_string/to_string
• 4: https://en.cppreference.com/w/cpp/string/basic_string/to_string.html
• 5: https://stackoverflow.com/questions/66100083/c17-to-string-converts-floats-with-comma
• 6: https://stackoverflow.com/questions/29247777/is-stdto-string-guaranteed-to-include-a-decimal-point-when-converting-floating
• 7: Usage of std::to_string introduces locale-dependency where it shouldn't gnuradio/gnuradio#4241
• 8: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p2587r2.html

---

Match native float rendering to ESP32 Arduino.

ESP32 Arduino defaults String(float) to two decimal places, while the native stub uses six-digit std::to_string output. Keep the native behavior aligned with firmware by formatting the stub float constructor with two fixed decimal places and updating the float expectations to "interval":2.50 and "interval":0.00.

📍 Affects 2 files

• test/stubs/Arduino.h#L18-L18 (this comment)
• test/test_json_encode/test_main.cpp#L55-L58

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@test/stubs/Arduino.h` at line 18, Update the float constructor in String to
format values with fixed-point precision of two decimal places, matching ESP32
Arduino output. In test/stubs/Arduino.h lines 18-18, replace the default
std::to_string formatting; in test/test_json_encode/test_main.cpp lines 55-58,
update the float JSON expectations to `"interval":2.50` and `"interval":0.00`.