diff --git a/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenRepository.kt b/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenRepository.kt
index f4956cde3..5793e0ef2 100644
--- a/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenRepository.kt
+++ b/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenRepository.kt
@@ -124,7 +124,7 @@ class AppendableMavenRepository(
     }
 
     fun build(): Path {
-      if (!::existingJar.isInitialized) error("No jar file provided for $coordinate")
+      check(::existingJar.isInitialized) { "No jar file provided for $coordinate" }
       return existingJar.also {
         check(it.exists()) { "Jar file doesn't exist for $coordinate in: $it" }
         check(it.isRegularFile()) { "Jar is not a regular file for $coordinate in: $it" }
diff --git a/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/JarPath.kt b/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/JarPath.kt
index ffd80d546..13302d12d 100644
--- a/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/JarPath.kt
+++ b/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/JarPath.kt
@@ -30,7 +30,7 @@ fun ZipFile.getContent(entryName: String): String {
 }
 
 fun ZipFile.getStream(entryName: String): InputStream {
-  val entry = getEntry(entryName) ?: error("Entry $entryName not found in all entries: ${entries().toList()}")
+  val entry = requireNotNull(getEntry(entryName)) { "Entry $entryName not found in all entries: ${entries().toList()}" }
   return getInputStream(entry)
 }
 
diff --git a/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/RunProcess.kt b/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/RunProcess.kt
index c15413598..d9e3f5218 100644
--- a/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/RunProcess.kt
+++ b/src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/RunProcess.kt
@@ -9,8 +9,8 @@ fun runProcess(
   val err = process.errorStream.bufferedReader().use { it.readText() }
   val out = process.inputStream.bufferedReader().use { it.readText() }
 
-  if (exitCode != 0 || err.isNotEmpty()) {
-    error("Error occurred when running command line: $err")
+  check(exitCode == 0 && err.isEmpty()) {
+    "Error occurred when running command line: $err"
   }
 
   return out
diff --git a/src/main/kotlin/com/github/jengelman/gradle/plugins/shadow/transformers/TransformerContext.kt b/src/main/kotlin/com/github/jengelman/gradle/plugins/shadow/transformers/TransformerContext.kt
index 59c412e18..71e3f5cfa 100644
--- a/src/main/kotlin/com/github/jengelman/gradle/plugins/shadow/transformers/TransformerContext.kt
+++ b/src/main/kotlin/com/github/jengelman/gradle/plugins/shadow/transformers/TransformerContext.kt
@@ -18,7 +18,7 @@ public data class TransformerContext @JvmOverloads constructor(
     public fun relocators(relocators: Set<Relocator>): Builder = apply { this.relocators = relocators }
     public fun build(): TransformerContext = TransformerContext(
       path = path,
-      inputStream = inputStream ?: error("inputStream is required"),
+      inputStream = requireNotNull(inputStream) { "inputStream is required" },
       relocators = relocators,
     )
   }
diff --git a/src/test/kotlin/com/github/jengelman/gradle/plugins/shadow/transformers/ServiceFileTransformerTest.kt b/src/test/kotlin/com/github/jengelman/gradle/plugins/shadow/transformers/ServiceFileTransformerTest.kt
index 1b59c60be..28f539c8d 100644
--- a/src/test/kotlin/com/github/jengelman/gradle/plugins/shadow/transformers/ServiceFileTransformerTest.kt
+++ b/src/test/kotlin/com/github/jengelman/gradle/plugins/shadow/transformers/ServiceFileTransformerTest.kt
@@ -158,7 +158,7 @@ class ServiceFileTransformerTest : BaseTransformerTest<ServiceFileTransformer>()
     }
 
     fun ZipFile.getStream(entryName: String): InputStream {
-      val entry = getEntry(entryName) ?: error("Entry $entryName not found in all entries: ${entries().toList()}")
+      val entry = requireNotNull(getEntry(entryName)) { "Entry $entryName not found in all entries: ${entries().toList()}" }
       return getInputStream(entry)
     }