diff --git a/init/Android.mk b/init/Android.mk
index 1ca88d7..730ffc4 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -62,6 +62,7 @@
     action.cpp \
     capabilities.cpp \
     descriptors.cpp \
+    devices.cpp \
     import_parser.cpp \
     init_parser.cpp \
     log.cpp \
@@ -81,7 +82,6 @@
 LOCAL_SRC_FILES:= \
     bootchart.cpp \
     builtins.cpp \
-    devices.cpp \
     init.cpp \
     keychords.cpp \
     property_service.cpp \
@@ -138,6 +138,7 @@
 include $(CLEAR_VARS)
 LOCAL_MODULE := init_tests
 LOCAL_SRC_FILES := \
+    devices_test.cpp \
     init_parser_test.cpp \
     property_service_test.cpp \
     util_test.cpp \
diff --git a/init/devices.cpp b/init/devices.cpp
index 405f92e..6b7bab9 100644
--- a/init/devices.cpp
+++ b/init/devices.cpp
@@ -286,8 +286,7 @@
     }
 }
 
-static void add_platform_device(const char *path)
-{
+void add_platform_device(const char* path) {
     int path_len = strlen(path);
     struct platform_node *bus;
     const char *name = path;
@@ -329,8 +328,7 @@
     return NULL;
 }
 
-static void remove_platform_device(const char *path)
-{
+void remove_platform_device(const char* path) {
     struct listnode *node;
     struct platform_node *bus;
 
@@ -473,8 +471,7 @@
     }
 }
 
-static char **get_character_device_symlinks(struct uevent *uevent)
-{
+char** get_character_device_symlinks(struct uevent* uevent) {
     const char *parent;
     const char *slash;
     char **links;
@@ -526,8 +523,24 @@
     return NULL;
 }
 
-static char **get_block_device_symlinks(struct uevent *uevent)
-{
+// replaces any unacceptable characters with '_', the
+// length of the resulting string is equal to the input string
+void sanitize_partition_name(char* s) {
+    const char* accept =
+        "abcdefghijklmnopqrstuvwxyz"
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+        "0123456789"
+        "_-.";
+
+    if (!s) return;
+
+    while (*s) {
+        s += strspn(s, accept);
+        if (*s) *s++ = '_';
+    }
+}
+
+char** get_block_device_symlinks(struct uevent* uevent) {
     const char *device;
     struct platform_node *pdev;
     const char *slash;
@@ -562,7 +575,7 @@
 
     if (uevent->partition_name) {
         p = strdup(uevent->partition_name);
-        sanitize(p);
+        sanitize_partition_name(p);
         if (strcmp(uevent->partition_name, p)) {
             LOG(VERBOSE) << "Linking partition '" << uevent->partition_name << "' as '" << p << "'";
         }
diff --git a/init/devices.h b/init/devices.h
index 26a064b..1654af7 100644
--- a/init/devices.h
+++ b/init/devices.h
@@ -55,4 +55,11 @@
                          unsigned short wildcard);
 int get_device_fd();
 
-#endif	/* _INIT_DEVICES_H */
+// Exposed for testing
+void add_platform_device(const char* path);
+void remove_platform_device(const char* path);
+char** get_character_device_symlinks(uevent* uevent);
+char** get_block_device_symlinks(struct uevent* uevent);
+void sanitize_partition_name(char* s);
+
+#endif /* _INIT_DEVICES_H */
diff --git a/init/devices_test.cpp b/init/devices_test.cpp
new file mode 100644
index 0000000..f79c96d
--- /dev/null
+++ b/init/devices_test.cpp
@@ -0,0 +1,270 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#include "devices.h"
+
+#include <string>
+#include <vector>
+
+#include <android-base/scopeguard.h>
+#include <gtest/gtest.h>
+
+template <char** (*Function)(uevent*)>
+void test_get_symlinks(const std::string& platform_device_name, uevent* uevent,
+                       const std::vector<std::string> expected_links) {
+    add_platform_device(platform_device_name.c_str());
+    auto platform_device_remover = android::base::make_scope_guard(
+        [&platform_device_name]() { remove_platform_device(platform_device_name.c_str()); });
+
+    char** result = Function(uevent);
+    auto result_freer = android::base::make_scope_guard([result]() {
+        if (result) {
+            for (int i = 0; result[i]; i++) {
+                free(result[i]);
+            }
+            free(result);
+        }
+    });
+
+    auto expected_size = expected_links.size();
+    if (expected_size == 0) {
+        ASSERT_EQ(nullptr, result);
+    } else {
+        ASSERT_NE(nullptr, result);
+        // First assert size is equal, so we don't overrun expected_links
+        unsigned int size = 0;
+        while (result[size]) ++size;
+        ASSERT_EQ(expected_size, size);
+
+        for (unsigned int i = 0; i < size; ++i) {
+            EXPECT_EQ(expected_links[i], result[i]);
+        }
+    }
+}
+
+TEST(devices, get_character_device_symlinks_success) {
+    const char* platform_device = "/devices/platform/some_device_name";
+    uevent uevent = {
+        .path = "/devices/platform/some_device_name/usb/usb_device/name/tty2-1:1.0",
+        .subsystem = "tty",
+    };
+    std::vector<std::string> expected_result{"/dev/usb/ttyname"};
+
+    test_get_symlinks<get_character_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_character_device_symlinks_no_pdev_match) {
+    const char* platform_device = "/devices/platform/some_device_name";
+    uevent uevent = {
+        .path = "/device/name/tty2-1:1.0", .subsystem = "tty",
+    };
+    std::vector<std::string> expected_result;
+
+    test_get_symlinks<get_character_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_character_device_symlinks_nothing_after_platform_device) {
+    const char* platform_device = "/devices/platform/some_device_name";
+    uevent uevent = {
+        .path = "/devices/platform/some_device_name", .subsystem = "tty",
+    };
+    std::vector<std::string> expected_result;
+
+    test_get_symlinks<get_character_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_character_device_symlinks_no_usb_found) {
+    const char* platform_device = "/devices/platform/some_device_name";
+    uevent uevent = {
+        .path = "/devices/platform/some_device_name/bad/bad/", .subsystem = "tty",
+    };
+    std::vector<std::string> expected_result;
+
+    test_get_symlinks<get_character_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_character_device_symlinks_no_roothub) {
+    const char* platform_device = "/devices/platform/some_device_name";
+    uevent uevent = {
+        .path = "/devices/platform/some_device_name/usb/", .subsystem = "tty",
+    };
+    std::vector<std::string> expected_result;
+
+    test_get_symlinks<get_character_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_character_device_symlinks_no_usb_device) {
+    const char* platform_device = "/devices/platform/some_device_name";
+    uevent uevent = {
+        .path = "/devices/platform/some_device_name/usb/usb_device/", .subsystem = "tty",
+    };
+    std::vector<std::string> expected_result;
+
+    test_get_symlinks<get_character_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_character_device_symlinks_no_final_slash) {
+    const char* platform_device = "/devices/platform/some_device_name";
+    uevent uevent = {
+        .path = "/devices/platform/some_device_name/usb/usb_device/name", .subsystem = "tty",
+    };
+    std::vector<std::string> expected_result;
+
+    test_get_symlinks<get_character_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_character_device_symlinks_no_final_name) {
+    const char* platform_device = "/devices/platform/some_device_name";
+    uevent uevent = {
+        .path = "/devices/platform/some_device_name/usb/usb_device//", .subsystem = "tty",
+    };
+    std::vector<std::string> expected_result;
+
+    test_get_symlinks<get_character_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_block_device_symlinks_success_platform) {
+    // These are actual paths from bullhead
+    const char* platform_device = "/devices/soc.0/f9824900.sdhci";
+    uevent uevent = {
+        .path = "/devices/soc.0/f9824900.sdhci/mmc_host/mmc0/mmc0:0001/block/mmcblk0",
+        .partition_name = nullptr,
+        .partition_num = -1,
+    };
+    std::vector<std::string> expected_result{"/dev/block/platform/soc.0/f9824900.sdhci/mmcblk0"};
+
+    test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_block_device_symlinks_success_platform_with_partition) {
+    // These are actual paths from bullhead
+    const char* platform_device = "/devices/soc.0/f9824900.sdhci";
+    uevent uevent = {
+        .path = "/devices/soc.0/f9824900.sdhci/mmc_host/mmc0/mmc0:0001/block/mmcblk0p1",
+        .partition_name = "modem",
+        .partition_num = 1,
+    };
+    std::vector<std::string> expected_result{
+        "/dev/block/platform/soc.0/f9824900.sdhci/by-name/modem",
+        "/dev/block/platform/soc.0/f9824900.sdhci/by-num/p1",
+        "/dev/block/platform/soc.0/f9824900.sdhci/mmcblk0p1",
+    };
+
+    test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_block_device_symlinks_success_platform_with_partition_only_num) {
+    const char* platform_device = "/devices/soc.0/f9824900.sdhci";
+    uevent uevent = {
+        .path = "/devices/soc.0/f9824900.sdhci/mmc_host/mmc0/mmc0:0001/block/mmcblk0p1",
+        .partition_name = nullptr,
+        .partition_num = 1,
+    };
+    std::vector<std::string> expected_result{
+        "/dev/block/platform/soc.0/f9824900.sdhci/by-num/p1",
+        "/dev/block/platform/soc.0/f9824900.sdhci/mmcblk0p1",
+    };
+
+    test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_block_device_symlinks_success_platform_with_partition_only_name) {
+    const char* platform_device = "/devices/soc.0/f9824900.sdhci";
+    uevent uevent = {
+        .path = "/devices/soc.0/f9824900.sdhci/mmc_host/mmc0/mmc0:0001/block/mmcblk0p1",
+        .partition_name = "modem",
+        .partition_num = -1,
+    };
+    std::vector<std::string> expected_result{
+        "/dev/block/platform/soc.0/f9824900.sdhci/by-name/modem",
+        "/dev/block/platform/soc.0/f9824900.sdhci/mmcblk0p1",
+    };
+
+    test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_block_device_symlinks_success_pci) {
+    const char* platform_device = "/devices/do/not/match";
+    uevent uevent = {
+        .path = "/devices/pci0000:00/0000:00:1f.2/mmcblk0",
+        .partition_name = nullptr,
+        .partition_num = -1,
+    };
+    std::vector<std::string> expected_result{"/dev/block/pci/pci0000:00/0000:00:1f.2/mmcblk0"};
+
+    test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_block_device_symlinks_success_vbd) {
+    const char* platform_device = "/devices/do/not/match";
+    uevent uevent = {
+        .path = "/devices/vbd-1234/mmcblk0", .partition_name = nullptr, .partition_num = -1,
+    };
+    std::vector<std::string> expected_result{"/dev/block/vbd/1234/mmcblk0"};
+
+    test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, get_block_device_symlinks_no_matches) {
+    const char* platform_device = "/devices/soc.0/f9824900.sdhci";
+    uevent uevent = {
+        .path = "/devices/soc.0/not_the_device/mmc_host/mmc0/mmc0:0001/block/mmcblk0p1",
+        .partition_name = nullptr,
+        .partition_num = -1,
+    };
+    std::vector<std::string> expected_result;
+
+    test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
+TEST(devices, sanitize_null) {
+    sanitize_partition_name(nullptr);
+}
+
+TEST(devices, sanitize_empty) {
+    std::string empty;
+    sanitize_partition_name(&empty[0]);
+    EXPECT_EQ(0u, empty.size());
+}
+
+TEST(devices, sanitize_allgood) {
+    std::string good =
+        "abcdefghijklmnopqrstuvwxyz"
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+        "0123456789"
+        "_-.";
+    std::string good_copy = good;
+    sanitize_partition_name(&good[0]);
+    EXPECT_EQ(good_copy, good);
+}
+
+TEST(devices, sanitize_somebad) {
+    std::string string = "abc!@#$%^&*()";
+    sanitize_partition_name(&string[0]);
+    EXPECT_EQ("abc__________", string);
+}
+
+TEST(devices, sanitize_allbad) {
+    std::string string = "!@#$%^&*()";
+    sanitize_partition_name(&string[0]);
+    EXPECT_EQ("__________", string);
+}
+
+TEST(devices, sanitize_onebad) {
+    std::string string = ")";
+    sanitize_partition_name(&string[0]);
+    EXPECT_EQ("_", string);
+}
diff --git a/init/util.cpp b/init/util.cpp
index bf4109c..c1b7898 100644
--- a/init/util.cpp
+++ b/init/util.cpp
@@ -235,27 +235,6 @@
     return 0;
 }
 
-/*
- * replaces any unacceptable characters with '_', the
- * length of the resulting string is equal to the input string
- */
-void sanitize(char *s)
-{
-    const char* accept =
-            "abcdefghijklmnopqrstuvwxyz"
-            "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-            "0123456789"
-            "_-.";
-
-    if (!s)
-        return;
-
-    while (*s) {
-        s += strspn(s, accept);
-        if (*s) *s++ = '_';
-    }
-}
-
 int wait_for_file(const char* filename, std::chrono::nanoseconds timeout) {
     boot_clock::time_point timeout_time = boot_clock::now() + timeout;
     while (boot_clock::now() < timeout_time) {
diff --git a/init/util.h b/init/util.h
index 1034c9b..38a7bdb 100644
--- a/init/util.h
+++ b/init/util.h
@@ -61,7 +61,6 @@
 unsigned int decode_uid(const char *s);
 
 int mkdir_recursive(const char *pathname, mode_t mode);
-void sanitize(char *p);
 int wait_for_file(const char *filename, std::chrono::nanoseconds timeout);
 void import_kernel_cmdline(bool in_qemu,
                            const std::function<void(const std::string&, const std::string&, bool)>&);