diff --git a/libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/unitTests/diagnosticsTests/ToolingDiagnosticOutputTest.kt b/libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/unitTests/diagnosticsTests/ToolingDiagnosticOutputTest.kt
new file mode 100644
index 0000000000000..dec8f9f74bd9a
--- /dev/null
+++ b/libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/unitTests/diagnosticsTests/ToolingDiagnosticOutputTest.kt
@@ -0,0 +1,153 @@
+/*
+ * Copyright 2010-2025 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+@file:Suppress("FunctionName")
+
+package org.jetbrains.kotlin.gradle.unitTests.diagnosticsTests
+
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.DiagnosticGroups
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.TerminalColorSupport.TerminalStyle.blue
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.TerminalColorSupport.TerminalStyle.bold
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.TerminalColorSupport.TerminalStyle.green
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.TerminalColorSupport.TerminalStyle.italic
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.TerminalColorSupport.TerminalStyle.lightBlue
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.TerminalColorSupport.TerminalStyle.orange
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.TerminalColorSupport.TerminalStyle.red
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.TerminalColorSupport.TerminalStyle.yellow
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.ToolingDiagnostic
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.plain
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.styled
+import kotlin.test.*
+
+class ToolingDiagnosticOutputTest {
+
+    @Test
+    fun `test plain diagnostic with warning severity`() {
+        val diagnostic = ToolingDiagnostic(
+            identifier = ToolingDiagnostic.ID("KT-1234", "Test Diagnostic", DiagnosticGroups.KGP.Deprecation),
+            message = "Detailed error description",
+            severity = ToolingDiagnostic.Severity.WARNING,
+            solutions = listOf("Try this fix"),
+        )
+
+        val plainOutput = diagnostic.plain(showEmoji = true)
+
+        assertEquals("⚠️ Test Diagnostic", plainOutput.name)
+        assertEquals("Detailed error description", plainOutput.message)
+        assertEquals("Solution: Try this fix", plainOutput.solution)
+        assertNull(plainOutput.documentation)
+    }
+
+    @Test
+    fun `test styled diagnostic with error severity`() {
+        val diagnostic = ToolingDiagnostic(
+            identifier = ToolingDiagnostic.ID("KT-5678", "Sample Diagnostic", DiagnosticGroups.KGP.Misconfiguration),
+            message = "Test error message",
+            severity = ToolingDiagnostic.Severity.ERROR,
+            solutions = listOf("First solution", "Second solution"),
+        )
+
+        val styledOutput = diagnostic.styled(showEmoji = true)
+
+        assertEquals("❌ Sample Diagnostic".bold().red(), styledOutput.name)
+        assertEquals("Test error message", styledOutput.message)
+        assertEquals(
+            buildString {
+                appendLine("Solutions:".bold().green())
+                appendLine(" • ${"First solution".italic()}".green())
+                append(" • ${"Second solution".italic()}".green())
+            },
+            styledOutput.solution
+        )
+    }
+
+    @Test
+    fun `test styled diagnostic with code blocks`() {
+        val messageWithCode = """
+            Invalid configuration found:
+            ```
+            kotlinOptions {
+                jvmTarget = "1.8"
+            }
+            ```
+            Please update to a newer version.
+        """.trimIndent()
+
+        val diagnostic = ToolingDiagnostic(
+            identifier = ToolingDiagnostic.ID("KT-9999", "Minimal Test", DiagnosticGroups.KGP.Experimental),
+            message = messageWithCode,
+            severity = ToolingDiagnostic.Severity.WARNING,
+            solutions = listOf("Fix the code")
+        )
+
+        val styledOutput = diagnostic.styled(showEmoji = true)
+
+        assertEquals("⚠️ Minimal Test".bold().yellow(), styledOutput.name)
+        assertEquals(buildString {
+            appendLine("Invalid configuration found:")
+            appendLine("kotlinOptions {".orange())
+            appendLine("    jvmTarget = \"1.8\"".orange())
+            appendLine("}".orange())
+            append("Please update to a newer version.")
+        }, styledOutput.message)
+        assertEquals(
+            buildString {
+                appendLine("Solution:".bold().green())
+                append("Fix the code".italic().green())
+            },
+            styledOutput.solution
+        )
+    }
+
+    @Test
+    fun `test plain diagnostic without emoji`() {
+        val diagnostic = ToolingDiagnostic(
+            identifier = ToolingDiagnostic.ID("KT-9999", "Minimal Test", DiagnosticGroups.KGP.Misconfiguration),
+            message = "Critical error occurred",
+            severity = ToolingDiagnostic.Severity.FATAL,
+            solutions = listOf("Fix the code")
+        )
+
+        val plainOutput = diagnostic.plain(showEmoji = false)
+
+        assertEquals("Minimal Test", plainOutput.name)
+        assertEquals("Critical error occurred", plainOutput.message)
+        assertEquals("Solution: Fix the code", plainOutput.solution)
+    }
+
+    @Test
+    fun `test styled diagnostic with documentation`() {
+        val diagnostic = ToolingDiagnostic(
+            identifier = ToolingDiagnostic.ID("KT-9999", "Minimal Test", DiagnosticGroups.KGP.Misconfiguration),
+            message = "Configuration warning",
+            severity = ToolingDiagnostic.Severity.WARNING,
+            solutions = listOf("Fix the code"),
+            documentation = ToolingDiagnostic.Documentation(
+                url = "https://kotlinlang.org/docs/home.html",
+                additionalUrlContext = "See the Kotlin documentation at https://kotlinlang.org/docs/home.html for more details"
+            )
+        )
+
+        val styledOutput = diagnostic.styled(showEmoji = true)
+
+        assertEquals("⚠️ Minimal Test".bold().yellow(), styledOutput.name)
+        assertEquals("Configuration warning", styledOutput.message)
+        assertEquals(
+            buildString {
+                appendLine("Solution:".bold().green())
+                append("Fix the code".italic().green())
+            },
+            styledOutput.solution
+        )
+        assertEquals(
+            buildString {
+                append("See the Kotlin documentation at ".lightBlue())
+                append("https://kotlinlang.org/docs/home.html".blue())
+                append(" for more details".lightBlue())
+            },
+            styledOutput.documentation
+        )
+    }
+}
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