Fix issue with empty line and add tests

Author: vmutafov

test-app/build-tools/android-metadata-generator/src/src/com/telerik/metadata/security/filtering/input/user/UserLineCommentFilter.kt renamed to test-app/build-tools/android-metadata-generator/src/src/com/telerik/metadata/security/filtering/input/user/UserLineFilter.kt

@@ -1,5 +1,6 @@
 package com.telerik.metadata.security.filtering.input.user
 
-class UserLineCommentFilter {
+class UserLineFilter {
     fun isCommentLine(line: String) = line.startsWith("//") || line.startsWith("#")
+    fun isEmptyLine(line: String) = line.isBlank()
 }

test-app/build-tools/android-metadata-generator/src/src/com/telerik/metadata/security/filtering/input/user/UserPatternsCollection.kt

@@ -40,10 +40,13 @@ object UserPatternsCollection : PatternsCollection {
     private fun parseFile(path: Path): Collection<PatternEntry> {
         val fileLines = Files.readAllLines(path)
         val lineSplitter = UserLineSplitter()
-        val commentFilter = UserLineCommentFilter()
+        val lineFilter = UserLineFilter()
 
         return fileLines
-                .filter { !commentFilter.isCommentLine(it) }
+                .asSequence()
+                .filter { !lineFilter.isCommentLine(it) }
+                .filter { !lineFilter.isEmptyLine(it) }
                 .map { lineSplitter.splitLine(it) }
+                .toList()
     }
 }

test-app/build-tools/android-metadata-generator/src/test/java/com/telerik/metadata/security/filtering/input/user/UserLineCommentFilterTest.kt renamed to test-app/build-tools/android-metadata-generator/src/test/java/com/telerik/metadata/security/filtering/input/user/UserLineFilterTest.kt

@@ -4,13 +4,13 @@ import org.junit.Test
 
 import org.junit.Assert.*
 
-class UserLineCommentFilterTest {
+class UserLineFilterTest {
 
     companion object {
         private const val UNEXPECTED_LINE_FILTERING_RESULT_MESSAGE = "Unexpected line filtering result"
     }
 
-    private val filter = UserLineCommentFilter()
+    private val filter = UserLineFilter()
 
     @Test
     fun `Is regular commented line`() {
@@ -38,4 +38,22 @@ class UserLineCommentFilterTest {
 
         assertFalse(UNEXPECTED_LINE_FILTERING_RESULT_MESSAGE, isComment)
     }
+
+    @Test
+    fun `Is empty line`(){
+        val line = System.lineSeparator()
+
+        val isEmptyLine = filter.isEmptyLine(line)
+
+        assertTrue(UNEXPECTED_LINE_FILTERING_RESULT_MESSAGE, isEmptyLine)
+    }
+
+    @Test
+    fun `Is whitespace line`(){
+        val line = "   "
+
+        val isEmptyLine = filter.isEmptyLine(line)
+
+        assertTrue(UNEXPECTED_LINE_FILTERING_RESULT_MESSAGE, isEmptyLine)
+    }
 }