NowChessSystems/docs/superpowers/plans/2026-03-22-scalatest-scoverage.md

ScalaTest + Scoverage Migration Implementation Plan

For agentic workers: REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (- [ ]) syntax for tracking.

Goal: Replace JaCoCo with Scoverage and add ScalaTest (with its JUnit 5 bridge) as the test library across all modules.

Architecture: Three build files are modified — the root for shared dependency versions, and each module for plugins, dependencies, and task wiring. No source files are created. The Scoverage Gradle plugin is applied per-module with its version hardcoded inline (Gradle resolves plugins {} before rootProject.extra is available).

Tech Stack: Scala 3, Gradle (Kotlin DSL), ScalaTest 3.2.19, scalatestplus-junit-5-11 3.2.19.1, Scoverage Gradle plugin 8.1.

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File Map

File	Change
build.gradle.kts (root)	Add SCALATEST and SCALATESTPLUS_JUNIT5 version entries
modules/core/build.gradle.kts	Replace jacoco with org.scoverage; swap JUnit deps for ScalaTest; merge two tasks.test {} blocks
modules/api/build.gradle.kts	Same as core; also add missing useJUnitPlatform()

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Task 1: Add ScalaTest version entries to root build

Files:

• Modify: build.gradle.kts (root)

• Step 1: Add version entries

Open build.gradle.kts at the root. The versions map currently looks like:

val versions = mapOf(
    "QUARKUS_SCALA3" to "1.0.0",
    "SCALA3"         to "3.5.1",
    "SCALA_LIBRARY"  to "2.13.18"
)

Add two entries so it becomes:

val versions = mapOf(
    "QUARKUS_SCALA3"        to "1.0.0",
    "SCALA3"                to "3.5.1",
    "SCALA_LIBRARY"         to "2.13.18",
    "SCALATEST"             to "3.2.19",
    "SCALATESTPLUS_JUNIT5"  to "3.2.19.1"
)

• Step 2: Verify the root build file parses

./gradlew help --quiet

Expected: exits 0 with no errors.

• Step 3: Commit

git add build.gradle.kts
git commit -m "build: add ScalaTest version entries to root versions map"

---

Task 2: Migrate modules/core to ScalaTest + Scoverage

Files:

• Modify: modules/core/build.gradle.kts

• Step 1: Replace the jacoco plugin with org.scoverage

In the plugins {} block, replace:

jacoco

with:

id("org.scoverage") version "8.1"

The full plugins block should be:

plugins {
    id("scala")
    id("org.scoverage") version "8.1"
    application
}

• Step 2: Swap JUnit dependencies for ScalaTest

In the dependencies {} block, remove:

testImplementation(platform("org.junit:junit-bom:5.10.0"))
testImplementation("org.junit.jupiter:junit-jupiter")
testRuntimeOnly("org.junit.platform:junit-platform-launcher")

Add in their place:

testImplementation("org.scalatest:scalatest_3:${versions["SCALATEST"]!!}")
testImplementation("org.scalatestplus:junit-5-11_3:${versions["SCALATESTPLUS_JUNIT5"]!!}")

• Step 3: Merge the two tasks.test {} blocks and replace jacoco wiring

The file currently has two separate tasks.test {} blocks and a tasks.jacocoTestReport {} block. Delete all three. Add the following single merged block after the dependencies {} block:

tasks.test {
    useJUnitPlatform()
    finalizedBy(tasks.reportScoverage)
}
tasks.reportScoverage {
    dependsOn(tasks.test)
}

• Step 4: Run the tests

./gradlew :modules:core:test

Expected: BUILD SUCCESSFUL. (Zero tests is fine — there are no test files yet. The build must not fail with dependency resolution or plugin errors.)

• Step 5: Run the coverage report

./gradlew :modules:core:reportScoverage

Expected: BUILD SUCCESSFUL. A report is generated under modules/core/build/reports/scoverage/.

• Step 6: Commit

git add modules/core/build.gradle.kts
git commit -m "build(core): replace JaCoCo with Scoverage, add ScalaTest dependencies"

---

Task 3: Migrate modules/api to ScalaTest + Scoverage

Files:

• Modify: modules/api/build.gradle.kts

• Step 1: Replace the jacoco plugin with org.scoverage

In the plugins {} block, replace:

jacoco

with:

id("org.scoverage") version "8.1"

The full plugins block should be:

plugins {
    id("scala")
    id("org.scoverage") version "8.1"
}

• Step 2: Swap JUnit dependencies for ScalaTest

In the dependencies {} block, remove:

testImplementation(platform("org.junit:junit-bom:5.10.0"))
testImplementation("org.junit.jupiter:junit-jupiter")
testRuntimeOnly("org.junit.platform:junit-platform-launcher")

Add in their place:

testImplementation("org.scalatest:scalatest_3:${versions["SCALATEST"]!!}")
testImplementation("org.scalatestplus:junit-5-11_3:${versions["SCALATESTPLUS_JUNIT5"]!!}")

• Step 3: Merge the two tasks.test {} blocks and replace jacoco wiring

The modules/api file also has two tasks.test {} blocks and a jacocoTestReport block. Delete all three. Add the following merged block after the dependencies {} block:

tasks.test {
    useJUnitPlatform()
    finalizedBy(tasks.reportScoverage)
}
tasks.reportScoverage {
    dependsOn(tasks.test)
}

Note: modules/api did not previously have useJUnitPlatform() — it is being added here, not preserved.

• Step 4: Run the tests

./gradlew :modules:api:test

Expected: BUILD SUCCESSFUL.

• Step 5: Run the coverage report

./gradlew :modules:api:reportScoverage

Expected: BUILD SUCCESSFUL. A report is generated under modules/api/build/reports/scoverage/.

• Step 6: Commit

git add modules/api/build.gradle.kts
git commit -m "build(api): replace JaCoCo with Scoverage, add ScalaTest dependencies"

---

Task 4: Full build verification

• Step 1: Run the full build

./gradlew build

Expected: BUILD SUCCESSFUL with no errors across all modules.

• Step 2: Confirm no JaCoCo references remain

grep -r "jacoco\|jacocoTestReport" --include="*.kts" .

Expected: no output (zero matches).