Issue 22 - Better logcat replace support

logcat/api/logcat.api

@@ -45,6 +45,7 @@ public final class logcat/LogcatLogger$Companion {
 	public final fun getLogger ()Llogcat/LogcatLogger;
 	public final fun install (Llogcat/LogcatLogger;)V
 	public final fun isInstalled ()Z
+	public final fun replace (Llogcat/LogcatLogger;)V
 	public final fun uninstall ()V
 }
 

logcat/src/main/java/logcat/LogcatLogger.kt

@@ -69,6 +69,16 @@ interface LogcatLogger {
         logger = NoLog
       }
     }
+
+    /**
+     * Replaces the current logger (if any) with a new logger.
+     */
+    fun replace(logger: LogcatLogger) {
+      synchronized(this) {
+        installedThrowable = RuntimeException("Previous logger installed here")
+        Companion.logger = logger
+      }
+    }
   }
 
   private object NoLog : LogcatLogger {
@@ -78,6 +88,6 @@ interface LogcatLogger {
       priority: LogPriority,
       tag: String,
       message: String
-    ) = error("Should never receive any log")
+    ) = Unit
   }
 }

logcat/src/test/java/logcat/LogcatTest.kt

@@ -146,6 +146,37 @@ class LogcatTest {
     assertThat(logger.latestLog!!.tag).isEqualTo(LogcatTest::class.java.simpleName)
   }
 
+  @Test fun `installing a new Logger when one was already present, logs an error`() {
+    TestLogcatLogger().apply { LogcatLogger.install(this) }.latestLog.let { latestLog ->
+      // Expect no logcat messages to start.
+      assertThat(latestLog).isNull()
+    }
+    TestLogcatLogger().apply { LogcatLogger.install(this) }.latestLog.let { latestLog ->
+      latestLog!!.let {
+        assertThat(it.tag).isEqualTo("LogcatLogger")
+        assertThat(it.priority).isEqualTo(LogPriority.ERROR)
+        assertThat(it.message).isNotEmpty()
+      }
+    }
+  }
+
+  @Test fun `replacing a Logger when one was already present, this is fine`() {
+    TestLogcatLogger().apply { LogcatLogger.install(this) }.latestLog.let { latestLog ->
+      // Expect no logcat messages to start.
+      assertThat(latestLog).isNull()
+    }
+    TestLogcatLogger().apply { LogcatLogger.replace(this) }.latestLog.let { latestLog ->
+      assertThat(latestLog).isNull()
+    }
+  }
+
+  @Test fun `replace is lenient, it is fine to replace when no Logger previously installed`() {
+    TestLogcatLogger().apply { LogcatLogger.replace(this) }.latestLog.let { latestLog ->
+      // Expect no logcat messages to start.
+      assertThat(latestLog).isNull()
+    }
+  }
+
   companion object {
     fun companionFunctionLog(
       message: () -> String