Temporary reference point for handling multiple shard coverage data

This will be later removed. Using lcov's merge mechanism combines every data even that are not relavant to the source file making it un reliable, another option would be to manually merge them which would again turn complicated when dealing with branch and function data on scale

scripts/src/java/org/oppia/android/scripts/common/BazelClient.kt

@@ -187,6 +187,31 @@ class BazelClient(private val rootDirectory: File, private val commandExecutor:
         "Coverage command output lines " +
         "with bazel tests --collect coverage: $coverageCommandOutputLines"
       )
+
+      val regex = """(.*/shard_\d+_of_\d+/coverage\.dat)""".toRegex()
+      val shardCoveragePaths = coverageCommandOutputLines
+        .flatMap { regex.findAll(it).map { matchResult ->
+          matchResult.value.trim()
+        }
+      }
+
+      println("Shard coverage path: $shardCoveragePaths")
+
+      val lcovCommand = buildString {
+        append("lcov ")
+        shardCoveragePaths.forEach { path ->
+          append("--add-tracefile $path ")
+        }
+        append("--output-file ${rootDirectory}/coverage_reports/lcov_combined.dat")
+      }
+
+      val process = ProcessBuilder(*lcovCommand.split(" ").toTypedArray())
+        .redirectErrorStream(true)
+        .start()
+
+      val output = process.inputStream.bufferedReader().readText()
+      println("Output: $output")
+
       return File(rootDirectory, "/bazel-out/_coverage/_coverage_report.dat").readLines()
     } else {
       println("In does not have Shard count")