strata_mobile_test: Automated Headless Mobile Orchestrator & Visual Regression Suite

The strata_mobile_test crate provides an automated test execution harness, pure-Rust Android Debug Bridge (ADB) client, multi-backend emulator orchestrator, foldable posture driver, and perceptual visual regression engine for Project Strata.

It enables cross-platform automated testing across Android and iOS targets without requiring human intervention or proprietary vendor test suites.

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Architectural Topology

┌────────────────────────────────────────────────────────────────────────┐
│                      strata_mobile_test Runner                         │
├────────────────────────────────────────────────────────────────────────┤
│                                                                        │
│   ┌─────────────────────┐   ┌───────────────────┐   ┌──────────────┐   │
│   │   Pure-Rust ADB     │   │  iOS simctl Host  │   │ Fold Posture │   │
│   │   Packet Codec      │   │   Mock Viewport   │   │  Controller  │   │
│   └──────────┬──────────┘   └─────────┬─────────┘   └───────┬──────┘   │
│              │                        │                     │          │
│              ▼                        ▼                     ▼          │
│   ┌────────────────────────────────────────────────────────────────┐   │
│   │                Automated Execution Pipeline                    │   │
│   │  (Device Discovery -> Posture Transition -> Monkey Fuzzing)      │   │
│   └───────────────────────────────┬────────────────────────────────┘   │
│                                   │                                    │
│                 ┌─────────────────┴─────────────────┐                  │
│                 ▼                                   ▼                  │
│   ┌───────────────────────────┐       ┌────────────────────────────┐   │
│   │      SSIM Visual Diff     │       │    Logcat Panic Trapping   │   │
│   │  (Perceptual Framebuffer) │       │   (Rust Backtrace Parser)  │   │
│   └───────────────────────────┘       └────────────────────────────┘   │
│                                                                        │
└────────────────────────────────────────────────────────────────────────┘

---

1. Pure-Rust ADB Client & Server Engine

To eliminate external dependencies on Google's standalone adb binary in continuous integration containers, strata_mobile_test implements the complete ADB wire protocol in native Rust:

Packet Framing & Codec (AdbPacketCodec)

The ADB protocol utilizes 24-byte packet headers containing command tags, arguments, payload lengths, CRC32 checksums, and bitwise magic inversions:

pub struct AdbPacket {
    pub command: u32,       // A_SYNC, A_CNXN, A_OPEN, A_OKAY, A_CLSE, A_WRTE
    pub arg0: u32,          // Local stream ID or protocol version
    pub arg1: u32,          // Remote stream ID or max payload
    pub data_length: u32,   // Payload byte count
    pub data_crc32: u32,    // Checksum of payload bytes
    pub magic: u32,         // command ^ 0xFFFFFFFF
}

The codec validates packet integrity by verifying magic == command ^ 0xFFFFFFFF and computing payload checksums before passing messages to stream channels.

Emulator Port Scanner (AdbPortScanner)

The harness auto-discovers running local Android emulators by scanning TCP loopback interfaces across the standard Android emulator port range (5555..=5585):

pub const STANDARD_EMULATOR_PORTS: std::ops::RangeInclusive<u16> = 5555..=5585;

pub struct AdbPortScanner;

impl AdbPortScanner {
    pub fn scan_local_emulators() -> Vec<AdbDevice> {
        // Scans even numbered console ports and odd numbered ADB communication ports
        // Establishes handshake to retrieve device serials and connection states
    }
}

In-Memory Mock ADB Server (MockAdbServer)

For hermetic unit testing without running heavy hypervisors, MockAdbServer simulates emulator state machines, responding to host:devices-l, shell:input, shell:cmd device_state, and port forwarding commands with spec-compliant OKAY / FAIL tokens.

---

2. Multi-Backend Emulator Orchestration

The harness supports dual backend targets: Android QEMU/KVM virtual devices and iOS Simulator environments.

Android Headless Lifecycle (android.rs)

Configures headless execution parameters for high-density CI runners:

• GPU Acceleration: Supports swiftshader_indirect (software Vulkan/GLES), host (native GPU pass-through), or off.
• KVM Acceleration Check: Validates /dev/kvm write permissions on Linux hosts to detect hardware virtualization support.
• Boot Telemetry Verification: Polls Android system properties via ADB shell until sys.boot_completed returns 1.

pub struct EmulatorConfig {
    pub avd_name: String,
    pub no_window: bool,
    pub gpu_mode: EmulatorGpuMode,
    pub memory_mb: u32,
    pub cores: u32,
}

Apple iOS Orchestration & Non-macOS Fallback (ios.rs)

On macOS hosts with Xcode installed, the harness interfaces with xcrun simctl to boot named runtimes (iPhone 16 Pro, iPad Pro). On Linux and Windows build agents, it activates MockIosViewport, mocking the CoreAnimation composition surface, safe-area insets, and Darwin display link timings without proprietary binaries:

pub enum AppleLicenseTier {
    NativeMacOsHost { simctl_path: PathBuf },
    HeadlessCrossPlatformMock { viewport: MockIosViewport },
}

---

3. Foldable & Dual-Screen Posture Engine

Strata natively adapts UI layouts to folding hinges, flexible OLED panels, and multi-display enclosures. The foldable.rs module models physical hinge angles and drives real-time posture changes on emulators:

    0° Hinge Angle          90° Hinge Angle          180° Hinge Angle
     [Closed Mode]         [Flex / Tabletop]            [Flat Canvas]
   ┌───────────────┐       ┌───────────────┐       ┌───────┬───────┐
   │  Cover Screen │       │ Top Display   │       │       │       │
   │               │       ├───────────────┤       │ Pane  │ Pane  │
   │               │       │ Bottom Screen │       │   A   │   B   │
   └───────────────┘       └───────────────┘       └───────┴───────┘

Posture States (FoldPosture)

1. Closed ($0^\circ$): Device is folded shut; input routes exclusively to the outer cover screen.
2. HalfOpened ($90^\circ$): Tabletop "Flex Mode" dividing the viewport across the physical hinge.
3. Flat ($180^\circ$): Continuous uninterrupted canvas across both panels.
4. Flipped ($360^\circ$): Folded backwards for single-hand presentation.

Display Crease Features (DisplayCreaseFeature)

pub struct DisplayCreaseFeature {
    pub x: u32,
    pub y: u32,
    pub width: u32,
    pub height: u32,
    pub is_vertical: bool,
    pub is_separating: bool,
}

Posture Command Emission (PostureCommandEmitter)

Emits emulator console control commands (emu posture <posture>) and Android framework device state switches (cmd device_state state <id>) to trigger runtime layout recalculations.

---

4. Perceptual Visual Regression Engine (SSIM)

Rather than raw pixel-byte hashing which breaks across differing GPU rasterization rounding rules and antialiasing passes, strata_mobile_test implements a first-principles Structural Similarity Index Measure (SSIM) algorithm (visual.rs).

Mathematical Formulation

Given reference image $x$ and candidate image $y$, SSIM evaluates luminance $l(x,y)$, contrast $c(x,y)$, and structure $s(x,y)$:

$$\text{SSIM}(x,y) = \frac{(2\mu_x\mu_y + C_1)(2\sigma_{xy} + C_2)}{(\mu_x^2 + \mu_y^2 + C_1)(\sigma_x^2 + \sigma_y^2 + C_2)}$$

Where:

• $C_1 = (K_1 L)^2 = (0.01 \times 255)^2 = 6.5025$
• $C_2 = (K_2 L)^2 = (0.03 \times 255)^2 = 58.5225$
• $\mu_x, \mu_y$: Local pixel luminance averages
• $\sigma_x^2, \sigma_y^2$: Local variances
• $\sigma_{xy}$: Cross-covariance of $x$ and $y$

pub struct VisualDiffResult {
    pub ssim_score: f32,
    pub is_match: bool,
    pub mismatched_pixels: usize,
    pub damage_rects: Vec<(u32, u32, u32, u32)>,
}

The engine pinpoints the minimal bounding box around visual anomalies (damage_rects), enabling automated CI reports to highlight exact layout regressions.

---

5. Chaos Monkey Stress Fuzzing

The stress.rs module subjects applications to random input permutations to detect state desynchronizations, layout deadlocks, and race conditions.

• Deterministic PRNG (FuzzRng): Seedable Linear Congruential Generator ensuring every fuzz sequence is 100% reproducible across machines.
• Event Matrix (MonkeyEvent):
  • Tap { x, y }
  • Drag { start_x, start_y, end_x, end_y, duration_ms }
  • MultiTouchPinch { center_x, center_y, scale }
  • HardwareKey { keycode } (Back, Home, Volume)
  • OrientationChange { orientation }
  • ThermalJolt { thermal_level }
• ADB Command Translation: Converts structured events into efficient input tap, input swipe, or input keyevent invocations.

---

6. Runtime Panic Interception & Logcat Parser

The logcat.rs subsystem hooks the Android logcat stream and iOS diagnostic logs to capture panics:

• PanicTrap: Maintains internal rings of intercepted panic strings.
• LogcatParser: Extracts Rust thread panic markers (thread 'main' panicked at '...'), file paths, line numbers, and backtraces. Intercepts Android JVM exceptions (FATAL EXCEPTION: main) and Mach-O crash signals (EXC_BAD_ACCESS, SIGSEGV).

---

Execution and Reporting

Running the complete automated mobile test suite:

use strata_mobile_test::{StrataMobileTestConfig, StrataMobileTestRunner};

let mut config = StrataMobileTestConfig::default();
config.test_foldable = true;
config.enable_monkey_fuzz = true;
config.fuzz_event_count = 100;

let mut runner = StrataMobileTestRunner::new(config);
let report = runner.execute();

assert!(report.passed);
println!("Tests Run: {}, Failed: {}, SSIM Score: {:.4}",
    report.tests_run, report.tests_failed, report.ssim_score);

Verification Commands

# Execute mobile test harness integration tests
cargo test -p strata_mobile_test