Increse coverage

.agents/guidelines

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+shared/guidelines

.agents/memory/MEMORY.md

@@ -6,6 +6,9 @@ See [README.md](README.md) for the format and routing rules.
 ## Feedback (validated patterns & corrections)
 
 - [copilot-review-request](feedback/copilot-review-request.md) — GraphQL `requestReviews` with `botIds: ["BOT_kgDOCnlnWA"]`; REST endpoint silently no-ops on re-requests.
+- [kotlin-test-formatting](feedback/kotlin-test-formatting.md) — `@Nested` should be on the same line as `inner class`, and backticked name on the next line.
+- [equals-tester](feedback/equals-tester.md) — Use Guava's `EqualsTester` for testing `equals()` and `hashCode()`.
+- [utility-class-testing](feedback/utility-class-testing.md) — Use `UtilityClassTest` as the base for testing utility classes.
 
 ## Project (durable context & rationale)
 

.agents/memory/feedback/kotlin-test-formatting.md

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+# Kotlin Test Formatting
+
+## Backticked inner classes
+
+When using backticked descriptive names for inner classes in Kotlin tests:
+1. The `@Nested` annotation must be on the same line as the `inner class` declaration.
+2. The backticked class name must be on the next line.
+
+### Correct example:
+```kotlin
+@Nested internal inner class
+`some descriptive name` {
+    // ...
+}
+```
+
+### Incorrect example:
+```kotlin
+@Nested
+internal inner class `some descriptive name` {
+    // ...
+}
+```

.agents/memory/feedback/utility-class-testing.md

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+# Utility class testing
+
+In Spine libraries, utility classes (classes with only static methods and a private constructor) should be tested using `UtilityClassTest` as a base class.
+
+## Why
+
+`UtilityClassTest` automatically:
+1. Verifies that the class is `final`.
+2. Verifies that it has exactly one private constructor.
+3. Verifies that the constructor throws an exception (usually `AssertionError`) or simply that it can be instantiated via reflection (depending on the implementation of `UtilityClassTest`), thus covering the private constructor for coverage purposes.
+
+## How
+
+### Kotlin
+
+Inherit from `UtilityClassTest<TargetClass>(TargetClass::class.java)`:
+
+```kotlin
+@DisplayName("`MyUtils` should")
+internal class MyUtilsSpec : UtilityClassTest<MyUtils>(MyUtils::class.java) {
+    // ... tests ...
+}
+```
+
+### Java
+
+Inherit from `UtilityClassTest<TargetClass>`:
+
+```java
+@DisplayName("`MyUtils` should")
+class MyUtilsTest extends UtilityClassTest<MyUtils> {
+
+    MyUtilsTest() {
+        super(MyUtils.class);
+    }
+    // ... tests ...
+}
+```

.agents/project.md

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+../docs/project.md