test: add multi-file FK integration tests for PGM003

Tests PGM003 (FK without covering index) across migration boundaries,
covering all changed-file combinations: only FK file, only index file,
both files, and all files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

src/input/liquibase_xml.rs

@@ -778,11 +778,7 @@ fn generate_add_fk_sql(
 /// Required fields (`table_name`, `column_names`) are passed as pre-validated
 /// parameters. Optional fields (`constraintName`, `schemaName`) are extracted
 /// from `attrs`.
-fn generate_add_pk_sql(
-    attrs: &[(String, String)],
-    table_name: &str,
-    column_names: &str,
-) -> String {
+fn generate_add_pk_sql(attrs: &[(String, String)], table_name: &str, column_names: &str) -> String {
     let constraint_name = get_attr(attrs, "constraintName").unwrap_or_default();
     let schema_name = get_attr(attrs, "schemaName");
 
@@ -1484,8 +1480,7 @@ mod tests {
         assert_eq!(units.len(), 1);
         let sql = &units[0].sql;
         assert_eq!(
-            sql,
-            "ALTER TABLE orders ADD FOREIGN KEY (user_id) REFERENCES users (id);",
+            sql, "ALTER TABLE orders ADD FOREIGN KEY (user_id) REFERENCES users (id);",
             "Expected valid FK SQL without CONSTRAINT keyword, got: {}",
             sql
         );

tests/fixtures/README.md

@@ -8,6 +8,7 @@ This directory contains test fixtures for pg-migration-lint.
   - `clean/` - All migrations correct, expect 0 findings
   - `all-rules/` - One violation per rule (PGM001-PGM011), expect 11 findings
   - `suppressed/` - All violations suppressed, expect 0 findings
+  - `fk-with-later-index/` - Tests PGM003 FK detection across migration boundaries
   - `liquibase-xml/` - Tests Liquibase fallback parser
 
 ## Usage

tests/fixtures/repos/fk-with-later-index/migrations/V001__create_tables.sql

@@ -0,0 +1,10 @@
+CREATE TABLE customers (
+    id serial PRIMARY KEY,
+    name text NOT NULL
+);
+
+CREATE TABLE orders (
+    id serial PRIMARY KEY,
+    customer_id integer NOT NULL,
+    total numeric(12,2) NOT NULL
+);

tests/fixtures/repos/fk-with-later-index/migrations/V002__add_fk.sql

@@ -0,0 +1,2 @@
+ALTER TABLE orders ADD CONSTRAINT fk_orders_customer
+    FOREIGN KEY (customer_id) REFERENCES customers(id);

tests/fixtures/repos/fk-with-later-index/migrations/V003__add_index.sql

@@ -0,0 +1 @@
+CREATE INDEX idx_orders_customer_id ON orders (customer_id);

tests/integration.rs

@@ -262,7 +262,10 @@ fn test_pgm004_finding_details() {
 fn test_pgm002_finding_details() {
     // V003 drops idx_customers_email WITHOUT CONCURRENTLY.
     // V001 is replayed as baseline (creates the index), V002 and V003 are changed.
-    let findings = lint_fixture("all-rules", &["V002__violations.sql", "V003__more_violations.sql"]);
+    let findings = lint_fixture(
+        "all-rules",
+        &["V002__violations.sql", "V003__more_violations.sql"],
+    );
     let pgm002: Vec<&Finding> = findings.iter().filter(|f| f.rule_id == "PGM002").collect();
 
     assert_eq!(pgm002.len(), 1, "Expected exactly 1 PGM002 finding");
@@ -1826,3 +1829,90 @@ fn test_sarif_and_sonarqube_finding_counts_match() {
         findings.len()
     );
 }
+
+// ===========================================================================
+// Cross-file FK detection (PGM003) with fk-with-later-index fixture
+// ===========================================================================
+
+#[test]
+fn test_fk_without_index_cross_file_only_fk_changed() {
+    // Only V002 is changed. V001 is replayed as history (creates tables).
+    // V002 adds FK on orders.customer_id but V003 (which adds the covering
+    // index) has NOT been replayed yet. PGM003 should fire because
+    // catalog_after has no covering index at this point.
+    let findings = lint_fixture("fk-with-later-index", &["V002__add_fk.sql"]);
+    let pgm003: Vec<&Finding> = findings.iter().filter(|f| f.rule_id == "PGM003").collect();
+
+    assert_eq!(
+        pgm003.len(),
+        1,
+        "Expected exactly 1 PGM003 finding for FK without index. Got:\n  {}",
+        format_findings(&findings)
+    );
+    assert!(
+        pgm003[0].message.contains("customer_id"),
+        "PGM003 message should mention 'customer_id'. Got: {}",
+        pgm003[0].message
+    );
+}
+
+#[test]
+fn test_fk_with_later_index_only_index_changed() {
+    // Only V003 is changed. V001 and V002 are replayed as history.
+    // The FK from V002 already exists in catalog_before, and V003 adds
+    // the covering index. Since V002 is not being linted, no PGM003
+    // should fire -- the FK was in a prior file, not in the current lint set.
+    let findings = lint_fixture("fk-with-later-index", &["V003__add_index.sql"]);
+    let pgm003: Vec<&Finding> = findings.iter().filter(|f| f.rule_id == "PGM003").collect();
+
+    assert!(
+        pgm003.is_empty(),
+        "PGM003 should NOT fire when only the index file is linted. Got:\n  {}",
+        format_findings(&findings)
+    );
+}
+
+#[test]
+fn test_fk_cross_file_both_changed() {
+    // Both V002 and V003 are changed. V001 is replayed as history.
+    // When linting V002: FK is added but no covering index yet -> PGM003 fires.
+    // When linting V003: index is added, no new FK in this file -> no PGM003.
+    let findings = lint_fixture(
+        "fk-with-later-index",
+        &["V002__add_fk.sql", "V003__add_index.sql"],
+    );
+    let pgm003: Vec<&Finding> = findings.iter().filter(|f| f.rule_id == "PGM003").collect();
+
+    assert_eq!(
+        pgm003.len(),
+        1,
+        "Expected exactly 1 PGM003 finding (from V002 only). Got:\n  {}",
+        format_findings(&findings)
+    );
+    assert!(
+        pgm003[0].message.contains("customer_id"),
+        "PGM003 message should mention 'customer_id'. Got: {}",
+        pgm003[0].message
+    );
+}
+
+#[test]
+fn test_fk_cross_file_all_changed() {
+    // All files are changed (empty changed set). V001 creates tables (no FK,
+    // no finding). V002 adds FK without covering index -> PGM003 fires.
+    // V003 adds the covering index -> no additional PGM003.
+    let findings = lint_fixture("fk-with-later-index", &[]);
+    let pgm003: Vec<&Finding> = findings.iter().filter(|f| f.rule_id == "PGM003").collect();
+
+    assert_eq!(
+        pgm003.len(),
+        1,
+        "Expected exactly 1 PGM003 finding (from V002). Got:\n  {}",
+        format_findings(&findings)
+    );
+    assert!(
+        pgm003[0].message.contains("customer_id"),
+        "PGM003 message should mention 'customer_id'. Got: {}",
+        pgm003[0].message
+    );
+}