diff --git a/src/sbt-test/agent-1/confs/test.sbt b/src/sbt-test/agent-1/confs/test.sbt
index f791a5f..db66b90 100644
--- a/src/sbt-test/agent-1/confs/test.sbt
+++ b/src/sbt-test/agent-1/confs/test.sbt
@@ -5,7 +5,7 @@ def checkLog(logFile: String): Unit = {
   val log = IO.read(file(logFile))
 
   def expect(expected: String): Unit = {
-    assert(log contains expected, s"log should contain '$expected'")
+    assert(log.contains(expected), s"log should contain '$expected'")
   }
 
   expect("Agent 86")
diff --git a/src/sbt-test/agent-1/dist_1.9.x/test.sbt b/src/sbt-test/agent-1/dist_1.9.x/test.sbt
index cb605e2..990e2c9 100644
--- a/src/sbt-test/agent-1/dist_1.9.x/test.sbt
+++ b/src/sbt-test/agent-1/dist_1.9.x/test.sbt
@@ -11,7 +11,7 @@ TaskKey[Unit]("check") := {
     ((Universal / com.typesafe.sbt.packager.universal.UniversalPlugin.autoImport.stagingDirectory).value / "bin" / packageName.value).absolutePath.!!
 
   assert(
-    output contains "Agent 86",
+    output.contains("Agent 86"),
     "output does not include 'Agent 86'"
   )
 }
diff --git a/src/sbt-test/agent-1/test/test.sbt b/src/sbt-test/agent-1/test/test.sbt
index dcf2c4a..362bd60 100644
--- a/src/sbt-test/agent-1/test/test.sbt
+++ b/src/sbt-test/agent-1/test/test.sbt
@@ -21,7 +21,7 @@ TaskKey[Unit]("check") := {
   val testLog = IO.read(BuiltinCommands.lastLogFile(state.value).get)
 
   assert(
-    testLog contains "Agent 86",
+    testLog.contains("Agent 86"),
     "test log does not include 'Agent 86'"
   )
 }
diff --git a/src/sbt-test/agent/arguments/test.sbt b/src/sbt-test/agent/arguments/test.sbt
index b045fe0..7a8266d 100644
--- a/src/sbt-test/agent/arguments/test.sbt
+++ b/src/sbt-test/agent/arguments/test.sbt
@@ -32,19 +32,19 @@ TaskKey[Unit]("check") := {
     ((Universal / com.typesafe.sbt.packager.universal.UniversalPlugin.autoImport.stagingDirectory).value / "bin" / packageName.value).absolutePath.!!
 
   assert(
-    !(output contains "Agent 86"),
+    !output.contains("Agent 86"),
     "output includes 'Agent 86'"
   )
   assert(
-    !(output contains ";"),
+    !output.contains(";"),
     "output includes ';'"
   )
   assert(
-    output contains "Get_Smart",
+    output.contains("Get_Smart"),
     "output does not include 'Get_Smart'"
   )
   assert(
-    output contains "Agent_99",
+    output.contains("Agent_99"),
     "output does not include 'Agent_99'"
   )
 }
diff --git a/src/sbt-test/agent/compile/test.sbt b/src/sbt-test/agent/compile/test.sbt
index 5271ea5..c4c35ff 100644
--- a/src/sbt-test/agent/compile/test.sbt
+++ b/src/sbt-test/agent/compile/test.sbt
@@ -7,7 +7,7 @@ TaskKey[Unit]("checkDependency") := {
 }
 
 def expect(name: String, contents: String, expected: String): Unit =
-  assert(contents contains expected, s"$name should contain '$expected'")
+  assert(contents.contains(expected), s"$name should contain '$expected'")
 
 TaskKey[Unit]("checkLog") := {
   val log = IO.read(file("run.log"))
diff --git a/src/sbt-test/agent/dist/test.sbt b/src/sbt-test/agent/dist/test.sbt
index cb605e2..990e2c9 100644
--- a/src/sbt-test/agent/dist/test.sbt
+++ b/src/sbt-test/agent/dist/test.sbt
@@ -11,7 +11,7 @@ TaskKey[Unit]("check") := {
     ((Universal / com.typesafe.sbt.packager.universal.UniversalPlugin.autoImport.stagingDirectory).value / "bin" / packageName.value).absolutePath.!!
 
   assert(
-    output contains "Agent 86",
+    output.contains("Agent 86"),
     "output does not include 'Agent 86'"
   )
 }
diff --git a/src/sbt-test/agent/named/test.sbt b/src/sbt-test/agent/named/test.sbt
index 62a0ae3..02ba3f3 100644
--- a/src/sbt-test/agent/named/test.sbt
+++ b/src/sbt-test/agent/named/test.sbt
@@ -11,7 +11,7 @@ TaskKey[Unit]("check") := {
     ((Universal / com.typesafe.sbt.packager.universal.UniversalPlugin.autoImport.stagingDirectory).value / "bin" / packageName.value).absolutePath.!!
 
   assert(
-    output contains "Agent 86",
+    output.contains("Agent 86"),
     "output does not include 'Agent 86'"
   )
 }
diff --git a/src/sbt-test/agent/provided/test.sbt b/src/sbt-test/agent/provided/test.sbt
index 00814ca..73c09b1 100644
--- a/src/sbt-test/agent/provided/test.sbt
+++ b/src/sbt-test/agent/provided/test.sbt
@@ -1,6 +1,6 @@
 TaskKey[Unit]("check") := {
   def expect(name: String, contents: String, expected: String): Unit =
-    assert(contents contains expected, s"$name should contain '$expected'")
+    assert(contents.contains(expected), s"$name should contain '$expected'")
 
   val log = IO.read(file("run.log"))
 
diff --git a/src/sbt-test/agent/run/test.sbt b/src/sbt-test/agent/run/test.sbt
index c1abaec..012e961 100644
--- a/src/sbt-test/agent/run/test.sbt
+++ b/src/sbt-test/agent/run/test.sbt
@@ -20,7 +20,7 @@ TaskKey[Unit]("check") := {
   val runLog = IO.read(file("run.log"))
 
   assert(
-    runLog contains "Agent 86",
+    runLog.contains("Agent 86"),
     "run log does not include 'Agent 86'"
   )
 }
diff --git a/src/sbt-test/agent/test_and_dist/test.sbt b/src/sbt-test/agent/test_and_dist/test.sbt
index e84c1e7..43287b0 100644
--- a/src/sbt-test/agent/test_and_dist/test.sbt
+++ b/src/sbt-test/agent/test_and_dist/test.sbt
@@ -28,7 +28,7 @@ TaskKey[Unit]("check") := {
     ((Universal / com.typesafe.sbt.packager.universal.UniversalPlugin.autoImport.stagingDirectory).value / "bin" / packageName.value).absolutePath.!!
 
   assert(
-    output contains "Agent 86",
+    output.contains("Agent 86"),
     "output does not include 'Agent 86'"
   )
 
diff --git a/src/sbt-test/agent/test_no_dist/test.sbt b/src/sbt-test/agent/test_no_dist/test.sbt
index 362ef6d..ef190fa 100644
--- a/src/sbt-test/agent/test_no_dist/test.sbt
+++ b/src/sbt-test/agent/test_no_dist/test.sbt
@@ -28,7 +28,7 @@ TaskKey[Unit]("check") := {
     ((Universal / com.typesafe.sbt.packager.universal.UniversalPlugin.autoImport.stagingDirectory).value / "bin" / packageName.value).absolutePath.!!
 
   assert(
-    !(output contains "Agent 86"),
+    !output.contains("Agent 86"),
     "output include 'Agent 86'"
   )