Added a module for shared test utils

[koperagen]

It will be internal, and doesn't really change much - only one instance of code duplication is removed. But we'll have a capacity to use common code for all tests. For example, i'd like to later use those "shouldHaveColumn", etc in Arrow tests

[Jolanrensen]

Seems like a good idea! These helpers could also be beneficial there, I think:

dataframe/dataframe-jdbc/src/test/kotlin/org/jetbrains/kotlinx/dataframe/io/commonTestScenarios.kt

Line 149 in 6f63b4e

fun AnyFrame.assertInferredTypesMatchSchema() {

I'd also consider adding the testImplementation dependency in the dfbuild.kotlinJvmCommon convention plugin so we have less duplication and the utils will be available everywhere automatically.

[Copilot]

Pull request overview

Introduces a new internal Gradle submodule (:common-test-utils) to host shared test helper utilities, and wires it into existing modules’ test classpaths to reduce duplicated test code.

Changes:

• Added :common-test-utils module and included it in the build.
• Moved common debug/assertion helpers into common-test-utils and updated tests to import them.
• Added testImplementation(projects.commonTestUtils) across multiple modules’ test dependencies and removed duplicated helpers from core tests.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
settings.gradle.kts	Registers the new common-test-utils subproject.
dataframe-json/src/test/kotlin/org/jetbrains/kotlinx/dataframe/io/JsonTests.kt	Switches to shared alsoDebug import and removes local duplicate implementation.
dataframe-json/build.gradle.kts	Adds commonTestUtils as a test dependency.
dataframe-jdbc/build.gradle.kts	Adds commonTestUtils as a test dependency.
dataframe-geo/build.gradle.kts	Adds commonTestUtils as a test dependency.
dataframe-excel/build.gradle.kts	Adds commonTestUtils as a test dependency.
dataframe-csv/build.gradle.kts	Adds commonTestUtils as a test dependency.
dataframe-arrow/build.gradle.kts	Adds commonTestUtils as a test dependency.
core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/Utils.kt	Removes duplicated debug/assertion helpers now hosted in common-test-utils.
core/build.gradle.kts	Adds commonTestUtils as a test dependency for core tests that use the helpers.
common-test-utils/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DebugUtils.kt	New shared debug/assertion utilities (alsoDebug, toDebugString, shouldHaveColumn*).
common-test-utils/README.md	Adds brief documentation for the internal test utils module.
common-test-utils/build.gradle.kts	Defines the new module’s build and dependencies.

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[koperagen]

I'd also consider adding the testImplementation dependency in the dfbuild.kotlinJvmCommon convention plugin so we have less duplication and the utils will be available everywhere automatically.

This will be our first convention plugin that also adds dependencies. Seems like a new approach to me, a bit different from JDK/etc - although i'm not sure why. Would you like to have it? For example Kotlin also has a lot of shared build conventions. But from what i can see all dependencies are still declared explicitly

[Jolanrensen]

This will be our first convention plugin that also adds dependencies. Seems like a new approach to me, a bit different from JDK/etc - although i'm not sure why. Would you like to have it? For example Kotlin also has a lot of shared build conventions. But from what i can see all dependencies are still declared explicitly

It will be just be test dependencies, though, so it probably will never hurt.

In #1661 I also mentioned the idea of having an "io-source" convention plugin, which could add dependencies { api(projects.core) } etc. which is a step further and could be discussed later.
(There are also some external plugins that add dependencies, so it's not too uncommon)