diff --git a/Userland/test_env.cpp b/Userland/test_env.cpp
new file mode 100644
index 00000000000..ce5467ecf9b
--- /dev/null
+++ b/Userland/test_env.cpp
@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2018-2020, Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void assert_env(const char* name, const char* value)
+{
+    char* result = getenv(name);
+    if (!result) {
+        perror("getenv");
+        printf("(When reading value for '%s'; we expected '%s'.)\n", name, value);
+        ASSERT(false);
+    }
+    if (strcmp(result, value) != 0) {
+        printf("Expected '%s', got '%s' instead.\n", value, result);
+        ASSERT(false);
+    }
+}
+
+static void test_getenv_preexisting()
+{
+    assert_env("HOME", "/home/anon");
+}
+
+static void test_puttenv()
+{
+    char* to_put = strdup("PUTENVTEST=HELLOPUTENV");
+    int rc = putenv(to_put);
+    if (rc) {
+        perror("putenv");
+        ASSERT(false);
+    }
+    assert_env("PUTENVTEST", "HELLOPUTENV");
+    // Do not free `to_put`!
+}
+
+static void test_settenv()
+{
+    int rc = setenv("SETENVTEST", "HELLO SETENV!", 0);
+    if (rc) {
+        perror("setenv");
+        ASSERT(false);
+    }
+    // This used to trigger a very silly bug! :)
+    assert_env("SETENVTEST", "HELLO SETENV!");
+
+    rc = setenv("SETENVTEST", "How are you today?", 0);
+    if (rc) {
+        perror("setenv");
+        ASSERT(false);
+    }
+    assert_env("SETENVTEST", "HELLO SETENV!");
+
+    rc = setenv("SETENVTEST", "Goodbye, friend!", 1);
+    if (rc) {
+        perror("setenv");
+        ASSERT(false);
+    }
+    assert_env("SETENVTEST", "Goodbye, friend!");
+}
+
+static void test_settenv_overwrite_empty()
+{
+    int rc = setenv("EMPTYTEST", "Forcefully overwrite non-existing envvar", 1);
+    if (rc) {
+        perror("setenv");
+        ASSERT(false);
+    }
+    assert_env("EMPTYTEST", "Forcefully overwrite non-existing envvar");
+}
+
+int main(int, char**)
+{
+#define RUNTEST(x)                      \
+    {                                   \
+        printf("Running " #x " ...\n"); \
+        x();                            \
+        printf("Success!\n");           \
+    }
+    RUNTEST(test_getenv_preexisting);
+    RUNTEST(test_puttenv);
+    RUNTEST(test_settenv);
+    RUNTEST(test_settenv_overwrite_empty);
+    printf("PASS\n");
+
+    return 0;
+}