# Test Client - `TestClient`

You can use the `TestClient` class to test FastAPI applications without creating an actual HTTP and socket connection, just communicating directly with the FastAPI code.

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```

package cmd

import (
	"testing"
)

// Tests - mkdirAll()
func TestOSMkdirAll(t *testing.T) {
	// create xlStorage test setup
	_, path, err := newXLStorageTestSetup(t)
	if err != nil {
		t.Fatalf("Unable to create xlStorage test setup, %s", err)
	}

	if err = mkdirAll("", 0o777, ""); err != errInvalidArgument {
		t.Fatal("Unexpected error", err)
	}

import java.util.List;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;

/**
 * Test suite covering {@link Longs#asList(long[])}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullUnmarked
@AndroidIncompatible // test-suite builders
public class LongArrayAsListTest extends TestCase {

import java.util.List;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;

/**
 * Test suite covering {@link Shorts#asList(short[])}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullUnmarked
@AndroidIncompatible // test-suite builders
public class ShortArrayAsListTest extends TestCase {

import java.util.List;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;

/**
 * Test suite covering {@link Chars#asList(char[])}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullUnmarked
@AndroidIncompatible // test-suite builders
public class CharArrayAsListTest extends TestCase {

import java.util.List;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;

/**
 * Test suite covering {@link Shorts#asList(short[])}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullUnmarked
@AndroidIncompatible // test-suite builders
public class ShortArrayAsListTest extends TestCase {

 * governing permissions and limitations under the License.
 */
package org.codelibs.core.lang;

import org.junit.Test;

/**
 * @author wyukawa
 *
 */
public class SystemUtilTest {

    /**
     * @throws Exception
     */
    @Test
    public void test() throws Exception {
        System.out.println(SystemUtil.FILE_ENCODING);
        System.out.println(SystemUtil.LINE_SEPARATOR);

import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code containsKey()} operations on a map. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")

/**
 * A generic JUnit test which tests {@code toString()} operations on a map. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
 *
 * @author Kevin Bourrillion
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")

import org.junit.Ignore;

/**
 * A generic JUnit test which tests operations on a SortedSet. Can't be invoked directly; please see
 * {@code SortedSetTestSuiteBuilder}.
 *
 * @author Jesse Wilson
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.