docs(bf-g6aqi): document assert_exit_code method location and implementation state

notes/bf-g6aqi.md

@@ -0,0 +1,101 @@
+# Bead bf-g6aqi: Locate and examine assert_exit_code method implementation
+
+## Summary
+
+Located and examined the `assert_exit_code` method in the pdftract codebase.
+
+## Findings
+
+### 1. Method EXISTS on `TestExecutionResult` struct
+
+**Location:** `/home/coding/pdftract/tests/encryption_fixtures.rs` (lines 267-279)
+
+**Method signature:**
+```rust
+pub fn assert_exit_code(&self, expected: i32) -> &Self
+```
+
+**Implementation:**
+```rust
+pub fn assert_exit_code(&self, expected: i32) -> &Self {
+    let actual = self.exit_code();
+    let context = self.fixture_name.as_deref().unwrap_or("command");
+    assert_eq!(
+        actual,
+        Some(expected),
+        "Expected {} to exit with code {}, got {:?}",
+        context,
+        expected,
+        actual
+    );
+    self
+}
+```
+
+**Behavior:**
+- Asserts that the exit code matches an expected value
+- Returns `&Self` for method chaining
+- Provides clear error messages with context (fixture name or "command")
+- Handles cases where process was terminated by signal (returns `None` for exit code)
+
+**Usage pattern:**
+```rust
+result.assert_exit_code(3);  // Exits with code 3 for encryption errors
+result.assert_exit_code(0);  // Exits with code 0 for success
+```
+
+### 2. Method MISSING from `ExtractionResult` struct
+
+**Location:** `/home/coding/pdftract/crates/pdftract-core/src/extract.rs` (line 237)
+
+**Struct definition:**
+```rust
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+pub struct ExtractionResult {
+    pub fingerprint: String,
+    pub pages: Vec<PageResult>,
+    pub metadata: ExtractionMetadata,
+    pub signatures: Vec<SignatureJson>,
+    pub form_fields: Vec<FormFieldJson>,
+    pub links: Vec<LinkJson>,
+    pub attachments: Vec<AttachmentJson>,
+    pub threads: Vec<ThreadJson>,
+    #[serde(default)]
+    pub javascript_actions: Vec<JavascriptActionJson>,
+}
+```
+
+**Status:** NO impl block exists for `ExtractionResult` - the `assert_exit_code` method is NOT implemented on this struct.
+
+### 3. Other `ExtractionResult` in CER diff tool
+
+**Location:** `/home/coding/pdftract/crates/pdftract-cer-diff/src/main.rs` (lines 13-16)
+
+**Purpose:** Simple struct for JSON deserialization in CER diff tool
+
+**Status:** No impl block, no `assert_exit_code` method (not needed for this use case)
+
+## Test Coverage
+
+The `TestExecutionResult::assert_exit_code` method has comprehensive test coverage:
+
+**Passing test (line 762-773):**
+- `test_execution_result_assert_exit_code` - Verifies method panics when expected code doesn't match
+
+**Failing test (line 775-788):**
+- `test_execution_result_assert_exit_code_failure` - Verifies correct panic behavior with expected message
+
+**Method chaining test (line 979-996):**
+- `test_execution_result_method_chaining` - Demonstrates fluent API usage
+
+## Acceptance Criteria Status
+
+- ✅ Location of assert_exit_code method identified
+- ✅ Method signature documented
+- ✅ Current implementation state known (exists on TestExecutionResult, missing from ExtractionResult)
+- ✅ ExtractionResult structure understood
+
+## Conclusion
+
+The `assert_exit_code` method exists on `TestExecutionResult` (a test helper struct for CLI command execution) but does NOT exist on `ExtractionResult` (the core PDF extraction result struct). This is the expected state, as `ExtractionResult` is a data-carrying struct for PDF extraction output and does not need test assertion methods.