Moved string-formatting methods from Slog to Slogf.

Slog is a core class provided by frameworks.jar, and these new methods
were causing performance regressions, so they were moved to a
system_server only class.

Bug: 182476140
Bug: 183523451

Test: atest --rebuild-module-info FrameworksMockingServicesTests:SLogfTest

Change-Id: I98cbb122d5410b61812edc85162aa6b10b995fdc
diff --git a/core/java/android/util/Slog.java b/core/java/android/util/Slog.java
index 2a43222..78c4739 100644
--- a/core/java/android/util/Slog.java
+++ b/core/java/android/util/Slog.java
@@ -61,7 +61,10 @@
      * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
      * calling this method in a critical path, make sure to explicitly do the check before calling
      * it.
+     *
+     * @deprecated use {@code com.android.server.utils.SLogF} instead.
      */
+    @Deprecated
     public static void v(String tag, String format, @Nullable Object... args) {
         if (!Log.isLoggable(tag, Log.VERBOSE)) return;
 
@@ -87,7 +90,10 @@
      * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
      * calling this method in a critical path, make sure to explicitly do the check before calling
      * it.
+     *
+     * @deprecated use {@code com.android.server.utils.SLogF} instead.
      */
+    @Deprecated
     public static void d(String tag, String format, @Nullable Object... args) {
         if (!Log.isLoggable(tag, Log.DEBUG)) return;
 
@@ -112,7 +118,10 @@
      * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
      * calling this method in a critical path, make sure to explicitly do the check before calling
      * it.
+     *
+     * @deprecated use {@code com.android.server.utils.SLogF} instead.
      */
+    @Deprecated
     public static void i(String tag, String format, @Nullable Object... args) {
         if (!Log.isLoggable(tag, Log.INFO)) return;
 
@@ -142,7 +151,10 @@
      * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
      * calling this method in a critical path, make sure to explicitly do the check before calling
      * it.
+     *
+     * @deprecated use {@code com.android.server.utils.SLogF} instead.
      */
+    @Deprecated
     public static void w(String tag, String format, @Nullable Object... args) {
         if (!Log.isLoggable(tag, Log.WARN)) return;
 
@@ -157,7 +169,10 @@
      * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
      * calling this method in a critical path, make sure to explicitly do the check before calling
      * it.
+     *
+     * @deprecated use {@code com.android.server.utils.SLogF} instead.
      */
+    @Deprecated
     public static void w(String tag, Exception exception, String format, @Nullable Object... args) {
         if (!Log.isLoggable(tag, Log.WARN)) return;
 
@@ -183,7 +198,10 @@
      * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
      * calling this method in a critical path, make sure to explicitly do the check before calling
      * it.
+     *
+     * @deprecated use {@code com.android.server.utils.SLogF} instead.
      */
+    @Deprecated
     public static void e(String tag, String format, @Nullable Object... args) {
         if (!Log.isLoggable(tag, Log.ERROR)) return;
 
@@ -198,7 +216,10 @@
      * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
      * calling this method in a critical path, make sure to explicitly do the check before calling
      * it.
+     *
+     * @deprecated use {@code com.android.server.utils.SLogF} instead.
      */
+    @Deprecated
     public static void e(String tag, Exception exception, String format, @Nullable Object... args) {
         if (!Log.isLoggable(tag, Log.ERROR)) return;
 
@@ -217,14 +238,20 @@
 
     /**
      * Logs a {@code wtf} message.
+     *
+     * @deprecated use {@code com.android.server.utils.SLogF} instead.
      */
+    @Deprecated
     public static void wtf(String tag, String format, @Nullable Object... args) {
         wtf(tag, getMessage(format, args));
     }
 
     /**
      * Logs a {@code wtf} message with an exception.
+     *
+     * @deprecated use {@code com.android.server.utils.SLogF} instead.
      */
+    @Deprecated
     public static void wtf(String tag, Exception exception, String format,
             @Nullable Object... args) {
         wtf(tag, getMessage(format, args), exception);
diff --git a/services/Android.bp b/services/Android.bp
index c160842..81bb579 100644
--- a/services/Android.bp
+++ b/services/Android.bp
@@ -66,6 +66,11 @@
     visibility: ["//visibility:private"],
 }
 
+java_library {
+    name: "Slogf",
+    srcs: ["core/java/com/android/server/utils/Slogf.java"],
+}
+
 // merge all required services into one jar
 // ============================================================
 java_library {
diff --git a/services/core/java/com/android/server/utils/Slogf.java b/services/core/java/com/android/server/utils/Slogf.java
new file mode 100644
index 0000000..bbc5414
--- /dev/null
+++ b/services/core/java/com/android/server/utils/Slogf.java
@@ -0,0 +1,276 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.utils;
+
+import android.annotation.Nullable;
+import android.os.Trace;
+import android.util.Log;
+import android.util.Slog;
+import android.util.TimingsTraceLog;
+
+import com.android.internal.annotations.GuardedBy;
+
+import java.util.Formatter;
+import java.util.Locale;
+
+/**
+ * Extends {@link Slog} by providing overloaded methods that take string formatting.
+ *
+ * <p><strong>Note: </strong>the overloaded methods won't create the formatted message if the
+ * respective logging level is disabled for the tag, but the compiler will still create an
+ * intermediate array of the objects for the {@code vargars}, which could affect garbage collection.
+ * So, if you're calling these method in a critical path, make sure to explicitly check for the
+ * level before calling them.
+ */
+public final class Slogf {
+
+    @GuardedBy("sMessageBuilder")
+    private static final StringBuilder sMessageBuilder;
+
+    @GuardedBy("sMessageBuilder")
+    private static final Formatter sFormatter;
+
+    static {
+        TimingsTraceLog t = new TimingsTraceLog("SLog", Trace.TRACE_TAG_SYSTEM_SERVER);
+        t.traceBegin("static_init");
+        sMessageBuilder = new StringBuilder();
+        sFormatter = new Formatter(sMessageBuilder, Locale.ENGLISH);
+        t.traceEnd();
+    }
+
+    private Slogf() {
+        throw new UnsupportedOperationException("provides only static methods");
+    }
+
+    /** Same as {@link Log#isLoggable(String, int)}. */
+    public static boolean isLoggable(String tag, int level) {
+        return Log.isLoggable(tag, level);
+    }
+
+    /** Same as {@link Slog#v(String, String)}. */
+    public static int v(String tag, String msg) {
+        return Slog.v(tag, msg);
+    }
+
+    /** Same as {@link Slog#v(String, String, Throwable)}. */
+    public static int v(String tag, String msg, Throwable tr) {
+        return Slog.v(tag, msg, tr);
+    }
+
+    /** Same as {@link Slog#d(String, String)}. */
+    public static int d(String tag, String msg) {
+        return Slog.d(tag, msg);
+    }
+
+    /** Same as {@link Slog#d(String, String, Throwable)}. */
+    public static int d(String tag, String msg, Throwable tr) {
+        return Slog.d(tag, msg, tr);
+    }
+
+    /** Same as {@link Slog#i(String, String)}. */
+    public static int i(String tag, String msg) {
+        return Slog.i(tag, msg);
+    }
+
+    /** Same as {@link Slog#i(String, String, Throwable)}. */
+    public static int i(String tag, String msg, Throwable tr) {
+        return Slog.i(tag, msg, tr);
+    }
+
+    /** Same as {@link Slog#w(String, String)}. */
+    public static int w(String tag, String msg) {
+        return Slog.w(tag, msg);
+    }
+
+    /** Same as {@link Slog#w(String, String, Throwable)}. */
+    public static int w(String tag, String msg, Throwable tr) {
+        return Slog.w(tag, msg, tr);
+    }
+
+    /** Same as {@link Slog#w(String, String)}. */
+    public static int w(String tag, Throwable tr) {
+        return Slog.w(tag, tr);
+    }
+
+    /** Same as {@link Slog#e(String, String)}. */
+    public static int e(String tag, String msg) {
+        return Slog.e(tag, msg);
+    }
+
+    /** Same as {@link Slog#e(String, String, Throwable)}. */
+    public static int e(String tag, String msg, Throwable tr) {
+        return Slog.e(tag, msg, tr);
+    }
+
+    /** Same as {@link Slog#wtf(String, String)}. */
+    public static int wtf(String tag, String msg) {
+        return Slog.wtf(tag, msg);
+    }
+
+    /** Same as {@link Slog#wtfQuiet(String, String)}. */
+    public static void wtfQuiet(String tag, String msg) {
+        Slog.wtfQuiet(tag, msg);
+    }
+
+    /** Same as {@link Slog#wtfStack(String, String). */
+    public static int wtfStack(String tag, String msg) {
+        return Slog.wtfStack(tag, msg);
+    }
+
+    /** Same as {@link Slog#wtf(String, Throwable). */
+    public static int wtf(String tag, Throwable tr) {
+        return Slog.wtf(tag, tr);
+    }
+
+    /** Same as {@link Slog#wtf(String, String, Throwable)}. */
+    public static int wtf(String tag, String msg, Throwable tr) {
+        return Slog.wtf(tag, msg, tr);
+    }
+
+    /** Same as {@link Slog#println(int, String, String)}. */
+    public static int println(int priority, String tag, String msg) {
+        return Slog.println(priority, tag, msg);
+    }
+
+    /**
+     * Logs a {@link Log.VERBOSE} message.
+     *
+     * <p><strong>Note: </strong>the message will only be formatted if {@link Log#VERBOSE} logging
+     * is enabled for the given {@code tag}, but the compiler will still create an intermediate
+     * array of the objects for the {@code vargars}, which could affect garbage collection. So, if
+     * you're calling this method in a critical path, make sure to explicitly do the check before
+     * calling it.
+     */
+    public static void v(String tag, String format, @Nullable Object... args) {
+        if (!isLoggable(tag, Log.VERBOSE)) return;
+
+        v(tag, getMessage(format, args));
+    }
+
+    /**
+     * Logs a {@link Log.DEBUG} message.
+     *
+     * <p><strong>Note: </strong>the message will only be formatted if {@link Log#DEBUG} logging is
+     * enabled for the given {@code tag}, but the compiler will still create an intermediate array
+     * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
+     * calling this method in a critical path, make sure to explicitly do the check before calling
+     * it.
+     */
+    public static void d(String tag, String format, @Nullable Object... args) {
+        if (!isLoggable(tag, Log.DEBUG)) return;
+
+        d(tag, getMessage(format, args));
+    }
+
+    /**
+     * Logs a {@link Log.INFO} message.
+     *
+     * <p><strong>Note: </strong>the message will only be formatted if {@link Log#INFO} logging is
+     * enabled for the given {@code tag}, but the compiler will still create an intermediate array
+     * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
+     * calling this method in a critical path, make sure to explicitly do the check before calling
+     * it.
+     */
+    public static void i(String tag, String format, @Nullable Object... args) {
+        if (!isLoggable(tag, Log.INFO)) return;
+
+        i(tag, getMessage(format, args));
+    }
+
+    /**
+     * Logs a {@link Log.WARN} message.
+     *
+     * <p><strong>Note: </strong>the message will only be formatted if {@link Log#WARN} logging is
+     * enabled for the given {@code tag}, but the compiler will still create an intermediate array
+     * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
+     * calling this method in a critical path, make sure to explicitly do the check before calling
+     * it.
+     */
+    public static void w(String tag, String format, @Nullable Object... args) {
+        if (!isLoggable(tag, Log.WARN)) return;
+
+        w(tag, getMessage(format, args));
+    }
+
+    /**
+     * Logs a {@link Log.WARN} message with an exception
+     *
+     * <p><strong>Note: </strong>the message will only be formatted if {@link Log#WARN} logging is
+     * enabled for the given {@code tag}, but the compiler will still create an intermediate array
+     * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
+     * calling this method in a critical path, make sure to explicitly do the check before calling
+     * it.
+     */
+    public static void w(String tag, Exception exception, String format, @Nullable Object... args) {
+        if (!isLoggable(tag, Log.WARN)) return;
+
+        w(tag, getMessage(format, args), exception);
+    }
+    /**
+     * Logs a {@link Log.ERROR} message.
+     *
+     * <p><strong>Note: </strong>the message will only be formatted if {@link Log#ERROR} logging is
+     * enabled for the given {@code tag}, but the compiler will still create an intermediate array
+     * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
+     * calling this method in a critical path, make sure to explicitly do the check before calling
+     * it.
+     */
+    public static void e(String tag, String format, @Nullable Object... args) {
+        if (!isLoggable(tag, Log.ERROR)) return;
+
+        e(tag, getMessage(format, args));
+    }
+
+    /**
+     * Logs a {@link Log.ERROR} message with an exception
+     *
+     * <p><strong>Note: </strong>the message will only be formatted if {@link Log#ERROR} logging is
+     * enabled for the given {@code tag}, but the compiler will still create an intermediate array
+     * of the objects for the {@code vargars}, which could affect garbage collection. So, if you're
+     * calling this method in a critical path, make sure to explicitly do the check before calling
+     * it.
+     */
+    public static void e(String tag, Exception exception, String format, @Nullable Object... args) {
+        if (!isLoggable(tag, Log.ERROR)) return;
+
+        e(tag, getMessage(format, args), exception);
+    }
+
+    /**
+     * Logs a {@code wtf} message.
+     */
+    public static void wtf(String tag, String format, @Nullable Object... args) {
+        wtf(tag, getMessage(format, args));
+    }
+
+    /**
+     * Logs a {@code wtf} message with an exception.
+     */
+    public static void wtf(String tag, Exception exception, String format,
+            @Nullable Object... args) {
+        wtf(tag, getMessage(format, args), exception);
+    }
+
+    private static String getMessage(String format, @Nullable Object... args) {
+        synchronized (sMessageBuilder) {
+            sFormatter.format(format, args);
+            String message = sMessageBuilder.toString();
+            sMessageBuilder.setLength(0);
+            return message;
+        }
+    }
+}
diff --git a/services/tests/mockingservicestests/src/com/android/server/utils/SlogfTest.java b/services/tests/mockingservicestests/src/com/android/server/utils/SlogfTest.java
new file mode 100644
index 0000000..3e8cef9
--- /dev/null
+++ b/services/tests/mockingservicestests/src/com/android/server/utils/SlogfTest.java
@@ -0,0 +1,343 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.utils;
+
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.doReturn;
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.mockitoSession;
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.verify;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.never;
+
+import android.util.Log;
+import android.util.Slog;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.MockitoSession;
+import org.mockito.quality.Strictness;
+
+/**
+ * Run it as {@code atest FrameworksMockingServicesTests:SlogfTest}
+ */
+public final class SlogfTest {
+
+    private static final String TAG = SlogfTest.class.getSimpleName();
+
+    private MockitoSession mSession;
+
+    private final Exception mException = new Exception("D'OH!");
+
+    @Before
+    public void setup() {
+        mSession = mockitoSession()
+                .initMocks(this)
+                .mockStatic(Slog.class)
+                .spyStatic(Slogf.class) // for isLoggable only
+                .strictness(Strictness.LENIENT)
+                .startMocking();
+    }
+
+    @After
+    public void tearDown() {
+        if (mSession == null) {
+            Log.w(TAG, "finishSession(): no session");
+        } else {
+            mSession.finishMocking();
+        }
+    }
+
+    @Test
+    public void testIsLoggable() {
+        assertThat(Slogf.isLoggable(TAG, Log.VERBOSE)).isEqualTo(Log.isLoggable(TAG, Log.VERBOSE));
+    }
+
+    @Test
+    public void testV_msg() {
+        Slogf.v(TAG, "msg");
+
+        verify(()-> Slog.v(TAG, "msg"));
+    }
+
+    @Test
+    public void testV_msgAndException() {
+        Slogf.v(TAG, "msg", mException);
+
+        verify(()-> Slog.v(TAG, "msg", mException));
+    }
+
+    @Test
+    public void testV_msgFormatted_enabled() {
+        enableLogging(Log.VERBOSE);
+
+        Slogf.v(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.v(TAG, "msg in a bottle"));
+    }
+
+    @Test
+    public void testV_msgFormatted_disabled() {
+        disableLogging(Log.VERBOSE);
+
+        Slogf.v(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.v(eq(TAG), any()), never());
+    }
+
+    @Test
+    public void testD_msg() {
+        Slogf.d(TAG, "msg");
+
+        verify(()-> Slog.d(TAG, "msg"));
+    }
+
+    @Test
+    public void testD_msgAndException() {
+        Slogf.d(TAG, "msg", mException);
+
+        verify(()-> Slog.d(TAG, "msg", mException));
+    }
+
+    @Test
+    public void testD_msgFormatted_enabled() {
+        enableLogging(Log.DEBUG);
+
+        Slogf.d(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.d(TAG, "msg in a bottle"));
+    }
+
+    @Test
+    public void testD_msgFormatted_disabled() {
+        disableLogging(Log.DEBUG);
+
+        Slogf.d(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.d(eq(TAG), any()), never());
+    }
+
+    @Test
+    public void testI_msg() {
+        Slogf.i(TAG, "msg");
+
+        verify(()-> Slog.i(TAG, "msg"));
+    }
+
+    @Test
+    public void testI_msgAndException() {
+        Slogf.i(TAG, "msg", mException);
+
+        verify(()-> Slog.i(TAG, "msg", mException));
+    }
+
+    @Test
+    public void testI_msgFormatted_enabled() {
+        enableLogging(Log.INFO);
+
+        Slogf.i(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.i(TAG, "msg in a bottle"));
+    }
+
+    @Test
+    public void testI_msgFormatted_disabled() {
+        disableLogging(Log.INFO);
+
+        Slogf.i(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.i(eq(TAG), any()), never());
+    }
+
+    @Test
+    public void testW_msg() {
+        Slogf.w(TAG, "msg");
+
+        verify(()-> Slog.w(TAG, "msg"));
+    }
+
+    @Test
+    public void testW_msgAndException() {
+        Slogf.w(TAG, "msg", mException);
+
+        verify(()-> Slog.w(TAG, "msg", mException));
+    }
+
+    @Test
+    public void testW_exception() {
+        Slogf.w(TAG, mException);
+
+        verify(()-> Slog.w(TAG, mException));
+    }
+
+    @Test
+    public void testW_msgFormatted_enabled() {
+        enableLogging(Log.WARN);
+
+        Slogf.w(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.w(TAG, "msg in a bottle"));
+    }
+
+    @Test
+    public void testW_msgFormatted_disabled() {
+        disableLogging(Log.WARN);
+
+        Slogf.w(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.w(eq(TAG), any(String.class)), never());
+    }
+
+    @Test
+    public void testW_msgFormattedWithException_enabled() {
+        enableLogging(Log.WARN);
+
+        Slogf.w(TAG, mException, "msg in a %s", "bottle");
+
+        verify(()-> Slog.w(TAG, "msg in a bottle", mException));
+    }
+
+    @Test
+    public void testW_msgFormattedWithException_disabled() {
+        disableLogging(Log.WARN);
+
+        Slogf.w(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.w(eq(TAG), any(String.class), any(Throwable.class)), never());
+    }
+
+    @Test
+    public void testE_msg() {
+        Slogf.e(TAG, "msg");
+
+        verify(()-> Slog.e(TAG, "msg"));
+    }
+
+    @Test
+    public void testE_msgAndException() {
+        Slogf.e(TAG, "msg", mException);
+
+        verify(()-> Slog.e(TAG, "msg", mException));
+    }
+
+    @Test
+    public void testE_msgFormatted_enabled() {
+        enableLogging(Log.ERROR);
+
+        Slogf.e(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.e(TAG, "msg in a bottle"));
+    }
+
+    @Test
+    public void testE_msgFormatted_disabled() {
+        disableLogging(Log.ERROR);
+
+        Slogf.e(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.e(eq(TAG), any()), never());
+    }
+
+    @Test
+    public void testE_msgFormattedWithException_enabled() {
+        enableLogging(Log.ERROR);
+
+        Slogf.e(TAG, mException, "msg in a %s", "bottle");
+
+        verify(()-> Slog.e(TAG, "msg in a bottle", mException));
+    }
+
+    @Test
+    public void testE_msgFormattedWithException_disabled() {
+        disableLogging(Log.ERROR);
+
+        Slogf.e(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.e(eq(TAG), any(String.class), any(Throwable.class)), never());
+    }
+
+    @Test
+    public void testWtf_msg() {
+        Slogf.wtf(TAG, "msg");
+
+        verify(()-> Slog.wtf(TAG, "msg"));
+    }
+
+    @Test
+    public void testWtf_msgAndException() {
+        Slogf.wtf(TAG, "msg", mException);
+
+        verify(()-> Slog.wtf(TAG, "msg", mException));
+    }
+
+    @Test
+    public void testWtf_exception() {
+        Slogf.wtf(TAG, mException);
+
+        verify(()-> Slog.wtf(TAG, mException));
+    }
+
+    @Test
+    public void testWtf_msgFormatted() {
+        Slogf.wtf(TAG, "msg in a %s", "bottle");
+
+        verify(()-> Slog.wtf(TAG, "msg in a bottle"));
+    }
+
+    @Test
+    public void testWtfQuiet() {
+        Slogf.wtfQuiet(TAG, "msg");
+
+        verify(()-> Slog.wtfQuiet(TAG, "msg"));
+    }
+
+    @Test
+    public void testWtfStack() {
+        Slogf.wtfStack(TAG, "msg");
+
+        verify(()-> Slog.wtfStack(TAG, "msg"));
+    }
+
+    @Test
+    public void testPrintln() {
+        Slogf.println(42, TAG, "msg");
+
+        verify(()-> Slog.println(42, TAG, "msg"));
+    }
+
+    @Test
+    public void testWtf_msgFormattedWithException() {
+        Slogf.wtf(TAG, mException, "msg in a %s", "bottle");
+
+        verify(()-> Slog.wtf(TAG, "msg in a bottle", mException));
+    }
+
+    private void enableLogging(@Log.Level int level) {
+        setIsLogging(level, true);
+    }
+
+    private void disableLogging(@Log.Level int level) {
+        setIsLogging(level, false);
+    }
+
+    private void setIsLogging(@Log.Level int level, boolean value) {
+        doReturn(value).when(() -> Slogf.isLoggable(TAG, level));
+    }
+}