Make FormatStringConcatenation an error

Eight calls in the tests built a message or an expected string by
concatenation and handed it to a method that formats one itself:
AssertJ's describedAs, hasMessage and isEqualTo(String, Object...) and
Guava's checkState. They now pass a format string and its arguments.

Author: abashev

buildSrc/src/main/groovy/open-java-format.error-prone-conventions.gradle

@@ -55,6 +55,7 @@ tasks.withType(JavaCompile).configureEach {
 // Checks whose findings have been fixed, build-breaking so that new ones are fixed too rather than read past.
 tasks.withType(JavaCompile).configureEach {
     options.errorprone {
+        error('FormatStringConcatenation')
         error('RefactorSwitch')
         error('SameNameButDifferent')
         error('UnusedVariable')

gradle-open-java-format/src/test/java/com/palantir/javaformat/gradle/FormatDiffTest.java

@@ -104,7 +104,7 @@ private void runCommandInRepo(String... args) throws IOException, InterruptedExc
         process.getErrorStream().transferTo(baos);
         String stderr = baos.toString(UTF_8);
 
-        Preconditions.checkState(process.exitValue() == 0, "Expected return code of 0: " + stderr);
+        Preconditions.checkState(process.exitValue() == 0, "Expected return code of 0: %s", stderr);
     }
 
     private static Stream<FormatterService> getFormatters() throws IOException {

open-java-format-idea-plugin/src/test/java/com/palantir/javaformat/intellij/PalantirJavaFormatConfigurableTest.java

@@ -176,7 +176,7 @@ void showsTheActiveFormatterAsThePageStands() throws Throwable {
 
             useNativeImage.setSelected(true);
             assertThat(activeFormatter().getText())
-                    .isEqualTo("Need to download version " + pluginVersion + " from Maven Central");
+                    .isEqualTo("Need to download version %s from Maven Central", pluginVersion);
 
             path.setText("/opt/open-java-format");
             assertThat(activeFormatter().getText()).isEqualTo("/opt/open-java-format");
@@ -268,7 +268,7 @@ void refusesAPathThatIsNotAnExecutableFile() throws Throwable {
 
             assertThatThrownBy(configurable::apply)
                     .isInstanceOf(ConfigurationException.class)
-                    .hasMessage(missing + " is not an executable file");
+                    .hasMessage("%s is not an executable file", missing);
         });
     }
 

open-java-format/src/test/java/com/palantir/javaformat/java/FormatterIntegrationTest.java

@@ -79,7 +79,7 @@ public void format() {
                 tests.writeFormatterOutput(name, output);
                 return;
             }
-            assertThat(output).describedAs("bad output for " + name).isEqualTo(expected);
+            assertThat(output).describedAs("bad output for %s", name).isEqualTo(expected);
         } catch (FormatterException e) {
             throw new RuntimeException(String.format("Formatter crashed on %s", name), e);
         }
@@ -100,7 +100,7 @@ public void idempotentLF() {
         try {
             String mangled = expected.replace(separator, "\n");
             String output = createFormatter().formatSource(mangled);
-            assertThat(output).describedAs("bad output for " + name).isEqualTo(mangled);
+            assertThat(output).describedAs("bad output for %s", name).isEqualTo(mangled);
         } catch (FormatterException e) {
             throw new RuntimeException(String.format("Formatter crashed on %s", name), e);
         }
@@ -113,7 +113,7 @@ public void idempotentCR() {
         try {
             String mangled = expected.replace(separator, "\r");
             String output = createFormatter().formatSource(mangled);
-            assertThat(output).describedAs("bad output for " + name).isEqualTo(mangled);
+            assertThat(output).describedAs("bad output for %s", name).isEqualTo(mangled);
         } catch (FormatterException e) {
             throw new RuntimeException(String.format("Formatter crashed on %s", name), e);
         }
@@ -126,7 +126,7 @@ public void idempotentCRLF() {
         try {
             String mangled = expected.replace(separator, "\r\n");
             String output = createFormatter().formatSource(mangled);
-            assertThat(output).describedAs("bad output for " + name).isEqualTo(mangled);
+            assertThat(output).describedAs("bad output for %s", name).isEqualTo(mangled);
         } catch (FormatterException e) {
             throw new RuntimeException(String.format("Formatter crashed on %s", name), e);
         }

open-java-format/src/test/java/com/palantir/javaformat/java/JavaCommentsHelperTest.java

@@ -102,7 +102,7 @@ void theMissingSpaceRuleAppliesToEveryLineOfTheRun() throws Exception {
         // over as one tok (23 and later) or as one tok per line.
         String rewritten = rewrite("///Summary line.\n" + " ".repeat(COLUMN) + "///More text.", Style.OJF);
 
-        assertThat(rewritten).isEqualTo("/// Summary line.\n" + " ".repeat(COLUMN) + "/// More text.");
+        assertThat(rewritten).isEqualTo("/// Summary line.\n%s/// More text.", " ".repeat(COLUMN));
     }
 
     @Test