fix: update unit test and remove duplicate code

src/test/kotlin/io/snyk/plugin/ui/jcef/ApplyFixHandlerTest.kt

@@ -1,9 +1,9 @@
 package io.snyk.plugin.ui.jcef
 
 import org.junit.Test
-import junit.framework.TestCase.assertEquals
+import com.intellij.testFramework.fixtures.BasePlatformTestCase
 
-class DiffPatchTest {
+class DiffPatchTest : BasePlatformTestCase(){
     private  val originalFileContent = """
         /*
          * Copyright (c) 2014-2023 Bjoern Kimminich & the OWASP Juice Shop contributors.
@@ -46,8 +46,10 @@ class DiffPatchTest {
 
     @Test
     fun `test applying patch`() {
-        val diffPatch = parseDiff(responseDiff)
-        val patchedContent = applyPatch(originalFileContent, diffPatch)
+        val applyFixHandler = ApplyFixHandler(project)
+
+        val diffPatch = applyFixHandler.parseDiff(responseDiff)
+        val patchedContent = applyFixHandler.applyPatch(originalFileContent, diffPatch)
 
         val expectedPatchedContent = """
             /*
@@ -76,88 +78,4 @@ class DiffPatchTest {
 
         assertEquals(expectedPatchedContent, patchedContent)
     }
-
-    private fun applyPatch(fileContent: String, diffPatch: DiffPatch): String {
-        val lines = fileContent.lines().toMutableList()
-
-        for (hunk in diffPatch.hunks) {
-            var originalLineIndex = hunk.startLineOriginal - 1  // Convert to 0-based index
-
-            for (change in hunk.changes) {
-                when (change) {
-                    is Change.Addition -> {
-                        lines.add(originalLineIndex, change.line)
-                        originalLineIndex++
-                    }
-                    is Change.Deletion -> {
-                        if (originalLineIndex < lines.size && lines[originalLineIndex].trim() == change.line) {
-                            lines.removeAt(originalLineIndex)
-                        }
-                    }
-                    is Change.Context -> {
-                        originalLineIndex++  // Move past unchanged context lines
-                    }
-                }
-            }
-        }
-        return lines.joinToString("\n")
-    }
-
-    private fun parseDiff(diff: String): DiffPatch {
-        val lines = diff.lines()
-        val originalFile = lines.first { it.startsWith("---") }.substringAfter("--- ")
-        val fixedFile = lines.first { it.startsWith("+++") }.substringAfter("+++ ")
-
-        val hunks = mutableListOf<Hunk>()
-        var currentHunk: Hunk? = null
-        val changes = mutableListOf<Change>()
-
-        for (line in lines) {
-            when {
-                line.startsWith("@@") -> {
-                    // Parse hunk header (e.g., @@ -4,9 +4,14 @@)
-                    val hunkHeader = line.substringAfter("@@ ").substringBefore(" @@").split(" ")
-                    val original = hunkHeader[0].substring(1).split(",")
-                    val fixed = hunkHeader[1].substring(1).split(",")
-
-                    val startLineOriginal = original[0].toInt()
-                    val numLinesOriginal = original.getOrNull(1)?.toInt() ?: 1
-                    val startLineFixed = fixed[0].toInt()
-                    val numLinesFixed = fixed.getOrNull(1)?.toInt() ?: 1
-
-                    if (currentHunk != null) {
-                        hunks.add(currentHunk.copy(changes = changes.toList()))
-                        changes.clear()
-                    }
-                    currentHunk = Hunk(
-                        startLineOriginal = startLineOriginal,
-                        numLinesOriginal = numLinesOriginal,
-                        startLineFixed = startLineFixed,
-                        numLinesFixed = numLinesFixed,
-                        changes = emptyList()
-                    )
-                }
-
-                line.startsWith("---") || line.startsWith("+++") -> {
-                    // Skip file metadata lines (--- and +++)
-                    continue
-                }
-
-                line.startsWith("-") -> changes.add(Change.Deletion(line.substring(1).trim()))
-                line.startsWith("+") -> changes.add(Change.Addition(line.substring(1).trim()))
-                else -> changes.add(Change.Context(line.trim()))
-            }
-        }
-
-        // Add the last hunk
-        if (currentHunk != null) {
-            hunks.add(currentHunk.copy(changes = changes.toList()))
-        }
-
-        return DiffPatch(
-            originalFile = originalFile,
-            fixedFile = fixedFile,
-            hunks = hunks
-        )
-    }
 }