Fix part of #5343: Enable Code Coverage Analysis for many to one test target files

scripts/src/java/org/oppia/android/scripts/coverage/CoverageRunner.kt

@@ -71,6 +71,7 @@ class CoverageRunner(
         line.substringAfter(":").split(",")
       }
     }
+    println("Coverage Data props: $coverageDataProps")
 
     val filePath = coverageDataProps["SF"]?.firstOrNull()?.get(0)
     requireNotNull(filePath) { "File path not found" }

scripts/src/java/org/oppia/android/scripts/coverage/RunCoverage.kt

@@ -47,8 +47,8 @@ fun main(vararg args: String) {
 
   val reportOutputPath = getReportOutputPath(repoRoot, filePath, reportFormat)
 
-  if (!File(repoRoot, filePath).exists()) {
-    error("File doesn't exist: $filePath.")
+  check(File(repoRoot, filePath).exists()) {
+    "File doesn't exist: $filePath."
   }
 
   ScriptBackgroundCoroutineDispatcher().use { scriptBgDispatcher ->
@@ -113,8 +113,8 @@ class RunCoverage(
       println("This file is exempted from having a test file; skipping coverage check.")
     } else {
       val testFilePaths = findTestFiles(repoRoot, filePath)
-      if (testFilePaths.isEmpty()) {
-        error("No appropriate test file found for $filePath")
+      check(testFilePaths.isNotEmpty()) {
+        "No appropriate test file found for $filePath"
       }
 
       val testTargets = bazelClient.retrieveBazelTargets(testFilePaths)
@@ -150,7 +150,15 @@ private fun calculateAggregateCoverageReport(
     return coverages.find { it == Coverage.FULL } ?: Coverage.NONE
   }
 
-  val allCoveredLines = coverageReports.flatMap { it.coveredLineList }
+  val groupedCoverageReports = coverageReports.groupBy {
+    Pair(it.filePath, it.fileSha1Hash)
+  }
+
+  val singleCoverageReport = groupedCoverageReports.entries.single()
+  val (key, reports) = singleCoverageReport
+  val (filePath, fileSha1Hash) = key
+
+  val allCoveredLines = reports.flatMap { it.coveredLineList }
   val groupedCoveredLines = allCoveredLines.groupBy { it.lineNumber }
   val aggregatedCoveredLines = groupedCoveredLines.map { (lineNumber, coveredLines) ->
     CoveredLine.newBuilder()
@@ -161,13 +169,12 @@ private fun calculateAggregateCoverageReport(
 
   val totalLinesFound = aggregatedCoveredLines.size
   val totalLinesHit = aggregatedCoveredLines.count { it.coverage == Coverage.FULL }
-
-  val aggregatedTargetList = coverageReports.joinToString(separator = ", ") { it.bazelTestTarget }
+  val aggregatedTargetList = reports.joinToString(separator = ", ") { it.bazelTestTarget }
 
   return CoverageReport.newBuilder()
     .setBazelTestTarget(aggregatedTargetList)
-    .setFilePath(coverageReports.first().filePath)
-    .setFileSha1Hash(coverageReports.first().fileSha1Hash)
+    .setFilePath(filePath)
+    .setFileSha1Hash(fileSha1Hash)
     .addAllCoveredLine(aggregatedCoveredLines)
     .setLinesFound(totalLinesFound)
     .setLinesHit(totalLinesHit)

scripts/src/javatests/org/oppia/android/scripts/coverage/CoverageRunnerTest.kt

@@ -1,9 +1,6 @@
 package org.oppia.android.scripts.coverage
 
 import com.google.common.truth.Truth.assertThat
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.runBlocking
 import org.junit.After
 import org.junit.Before
 import org.junit.Rule
@@ -103,7 +100,7 @@ class CoverageRunnerTest {
   }
 
   @Test
-  fun testRetrieveCoverageDataForTestTarget_coverageRetrievalFailed_throwsException() {
+  fun testRetrieveCoverageDataForTestTarget_withIncorrectPackageStructure_throwsException() {
     testBazelWorkspace.initEmptyWorkspace()
     testBazelWorkspace.addSourceAndTestFileWithContent(
       filename = "AddNums",
@@ -124,11 +121,7 @@ class CoverageRunnerTest {
   }
 
   @Test
-  fun testRetrieveCoverageDataForTestTarget_coverageDataMissing_throwsException() {
-    val pattern = Regex(
-      ".*bazel-out/k8-fastbuild/testlogs/coverage/test/java/com/example/AddNumsTest/coverage.dat"
-    )
-
+  fun testRetrieveCoverageDataForTestTarget_withNoDepsToSourceFile_throwsException() {
     testBazelWorkspace.initEmptyWorkspace()
     testBazelWorkspace.addSourceAndTestFileWithContent(
       filename = "AddNums",
@@ -139,30 +132,47 @@ class CoverageRunnerTest {
       testSubpackage = "coverage/test/java/com/example"
     )
 
-    val exception = assertThrows<IllegalArgumentException>() {
-      runBlocking {
-        launch {
-          coverageRunner.retrieveCoverageDataForTestTarget(
-            "//coverage/test/java/com/example:AddNumsTest"
-          )
-        }
-
-        launch {
-          while (true) {
-            val dir = File(tempFolder.root.absolutePath.substringBeforeLast('/'))
-            dir.walkTopDown().firstOrNull { file ->
-              file.isFile && pattern.matches(file.absolutePath)
-            }?.apply {
-              if (exists()) {
-                delete()
-                createNewFile()
-              }
-              writeText("SF: coverage/test/java/com/example/IncorrectCoverageFile.kt")
-            }
-            delay(1)
+    val subTestFile = tempFolder.newFile("coverage/test/java/com/example/SubNumsTest.kt")
+    subTestFile.writeText(
+      """
+      package com.example
+
+      import org.junit.Assert.assertEquals
+      import org.junit.Test
+      import com.example.AddNums
+
+      class SubNumsTest {
+
+          @Test
+          fun testSubNumbers() {
+              assertEquals(AddNums.sumNumbers(0, 1), 1)
+              assertEquals(AddNums.sumNumbers(3, 4), 7)         
+              assertEquals(AddNums.sumNumbers(0, 0), "Both numbers are zero")
           }
-        }
       }
+      """.trimIndent()
+    )
+
+    val testBuildFile = File(tempFolder.root, "coverage/test/java/com/example/BUILD.bazel")
+    testBuildFile.appendText(
+      """
+      kt_jvm_test(
+          name = "SubNumsTest",
+          srcs = ["SubNumsTest.kt"],
+          deps = [
+            "//coverage/main/java/com/example:addnums",
+            "@maven//:junit_junit",
+          ],
+          visibility = ["//visibility:public"],
+          test_class = "com.example.SubNumsTest",
+      )
+      """.trimIndent()
+    )
+
+    val exception = assertThrows<IllegalArgumentException>() {
+      coverageRunner.retrieveCoverageDataForTestTarget(
+        "//coverage/test/java/com/example:SubNumsTest"
+      )
     }
 
     assertThat(exception).hasMessageThat().contains("Coverage data not found")