1 files changed, 19 insertions, 0 deletions
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/PrinterTest.java b/src/test/java/com/google/devtools/build/lib/syntax/PrinterTest.java
index 5adbd10b4e..c19d145936 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/PrinterTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/PrinterTest.java
@@ -15,6 +15,7 @@
 package com.google.devtools.build.lib.syntax;
 
 import static com.google.common.truth.Truth.assertThat;
+import static com.google.devtools.build.lib.testutil.MoreAsserts.assertThrows;
 import static org.junit.Assert.fail;
 
 import com.google.common.base.Joiner;
@@ -137,6 +138,24 @@ public class PrinterTest {
         "%.s");
   }
 
+  private SkylarkPrinter makeSimplifiedFormatPrinter() {
+    return new Printer.BasePrinter(new StringBuilder(), /*simplifiedFormatStrings=*/ true);
+  }
+
+  @Test
+  public void testSimplifiedDisallowsPlaceholdersBesidesPercentS() {
+    assertThat(makeSimplifiedFormatPrinter().format("Allowed: %%").toString())
+        .isEqualTo("Allowed: %");
+    assertThat(makeSimplifiedFormatPrinter().format("Allowed: %s", "abc").toString())
+        .isEqualTo("Allowed: abc");
+    assertThrows(
+        IllegalFormatException.class,
+        () -> makeSimplifiedFormatPrinter().format("Disallowed: %r", "abc"));
+    assertThrows(
+        IllegalFormatException.class,
+        () -> makeSimplifiedFormatPrinter().format("Disallowed: %d", 5));
+  }
+
   @Test
   public void testListLimitStringLength() throws Exception {
     int lengthDivisibleByTwo = Printer.SUGGESTED_CRITICAL_LIST_ELEMENTS_STRING_LENGTH;