Skip to content

πŸ§ͺ [Testing Improvement] Add edge case tests for percentile calculation #189

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
alvin000009238 wants to merge 1 commit into from
Closed

πŸ§ͺ [Testing Improvement] Add edge case tests for percentile calculation #189

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
20 changes: 20 additions & 0 deletions android/app/src/test/java/com/clhs/score/data/GradeAnalysisTest.kt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,26 @@ class GradeAnalysisTest {
assertEquals("前 27%", percentile(60.0, 219)?.percentLabel)
}

@Test
fun percentileReturnsNullForInvalidOrMissingInputs() {
assertNull(percentile(null, 37))
assertNull(percentile(13.0, null))
assertNull(percentile(13.0, 0))
assertNull(percentile(13.0, -5))
assertNull(percentile(0.0, 37))
assertNull(percentile(-5.0, 37))
}

@Test
fun percentileCoercesToValidRangeWhenRankExceedsCount() {
assertEquals(100, percentile(40.0, 37)?.topPercent)
}
Comment on lines +26 to +29

@gemini-code-assist gemini-code-assist Bot Jun 17, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

medium

The test asserts that percentile(40.0, 37) returns a valid PercentileInfo with topPercent = 100. However, a rank of 40 in a class of 37 (rank > count) is an invalid state. Allowing this to succeed means the UI might display an invalid rank label like "40/37".

Consider whether percentile should return null when rank > count to prevent displaying invalid data. If so, you can update percentile in GradeAnalysis.kt as follows:

fun percentile(rank: Double?, count: Int?): PercentileInfo? {
    if (rank == null || count == null || count <= 0 || rank > count) return null
    // ...
}

And update this test to assert assertNull instead.

Suggested change
@Test
fun percentileCoercesToValidRangeWhenRankExceedsCount() {
assertEquals(100, percentile(40.0, 37)?.topPercent)
}
@Test
fun percentileReturnsNullWhenRankExceedsCount() {
assertNull(percentile(40.0, 37))
}


@Test
fun percentileCoercesToValidRangeForTopRank() {
assertEquals(1, percentile(1.0, 1000)?.topPercent)
}

@Test
fun strengthAndWeaknessAreSortedByClassAverageDiff() {
val analysis = buildGradeAnalysis(MockGradeSystem.generateReport(StudentScenario.NORMAL))
Expand Down
Loading