diff --git a/composer.json b/composer.json
index c0814d9bf2..b11ab618a8 100644
--- a/composer.json
+++ b/composer.json
@@ -42,10 +42,7 @@
     "autoload": {
         "psr-4": {
             "DDTrace\\": "./src/api/"
-        },
-        "files": [
-            "./src/api/ComposerBootstrap.php"
-        ]
+        }
     },
     "autoload-dev": {
         "psr-4": {
diff --git a/src/api/ComposerBootstrap.php b/src/api/ComposerBootstrap.php
deleted file mode 100644
index 7482191d5f..0000000000
--- a/src/api/ComposerBootstrap.php
+++ /dev/null
@@ -1,9 +0,0 @@
-<?php
-
-namespace DDTrace;
-
-// The autoloading mechanism is explained in `docs/autoloading.md`. If this file is changed, make sure that
-// documentation is up to date.
-class ComposerBootstrap
-{
-}
diff --git a/src/api/Configuration.php b/src/api/Configuration.php
deleted file mode 100644
index 65662ff037..0000000000
--- a/src/api/Configuration.php
+++ /dev/null
@@ -1,251 +0,0 @@
-<?php
-
-namespace DDTrace;
-
-use DDTrace\Configuration\AbstractConfiguration;
-use DDTrace\Log\LoggingTrait;
-
-/**
- * DDTrace global configuration object.
- */
-class Configuration extends AbstractConfiguration
-{
-    use LoggingTrait;
-
-    /**
-     * Parsing sampling rules might be expensive so we cache values the first time we parse them.
-     *
-     * @var array
-     */
-    private $samplingRulesCache;
-
-    /**
-     * Whether or not tracing is enabled.
-     *
-     * @return bool
-     */
-    public function isEnabled()
-    {
-        return $this->boolValue('trace.enabled', true);
-    }
-
-    /**
-     * Whether or not debug mode is enabled.
-     *
-     * @return bool
-     */
-    public function isDebugModeEnabled()
-    {
-        return $this->boolValue('trace.debug', false);
-    }
-
-    /**
-     * Whether or not distributed tracing is enabled globally.
-     *
-     * @return bool
-     */
-    public function isDistributedTracingEnabled()
-    {
-        return $this->boolValue('distributed.tracing', true);
-    }
-
-    /**
-     * Whether or not automatic trace analytics configuration is enabled.
-     *
-     * @return bool
-     */
-    public function isAnalyticsEnabled()
-    {
-        return $this->boolValue('trace.analytics.enabled', false);
-    }
-
-    /**
-     * Whether or not priority sampling is enabled globally.
-     *
-     * @return bool
-     */
-    public function isPrioritySamplingEnabled()
-    {
-        return $this->isDistributedTracingEnabled()
-            && $this->boolValue('priority.sampling', true);
-    }
-
-    /**
-     * Whether or not also unfinished spans should be finished (and thus sent) when tracer is flushed.
-     * Motivation: We had users reporting that in some cases they have manual end-points that `echo` some content and
-     * then just `exit(0)` at the end of action's method. While the shutdown hook that flushes traces would still be
-     * called, many spans would be unfinished and thus discarded. With this option enabled spans are automatically
-     * finished (if not finished yet) when the tracer is flushed.
-     *
-     * @return bool
-     */
-    public function isAutofinishSpansEnabled()
-    {
-        return $this->boolValue('autofinish.spans', false);
-    }
-
-    /**
-     * Returns the sampling rate provided by the user. Default: 1.0 (keep all).
-     *
-     * @return float
-     */
-    public function getSamplingRate()
-    {
-        $value = $this->floatValue('trace.sample.rate', 1.0);
-        if ($value < 0) {
-            $value = 1;
-        } else {
-            $value = min(1, max(0, $value));
-        }
-        return $value;
-    }
-
-    /**
-     * Returns the sampling rules defined for the current service.
-     * Results are cached so it is perfectly fine to call this method multiple times.
-     * The expected format for sampling rule env variable is:
-     * - example: DD_TRACE_SAMPLING_RULES=[]
-     *        --> sample rate is 100%
-     * - example: DD_TRACE_SAMPLING_RULES=[{"sample_rate": 0.2}]
-     *        --> sample rate is 20%
-     * - example: DD_TRACE_SAMPLING_RULES=[{"service": "a.*", "name": "b", "sample_rate": 0.1}, {"sample_rate": 0.2}]
-     *        --> sample rate is 20% except for spans of service starting with 'a' and with name 'b' where rate is 10%
-     *
-     * Note that 'service' and 'name' is optional when when omitted the '*' pattern is assumed.
-     *
-     * @return array
-     */
-    public function getSamplingRules()
-    {
-        if (null !== $this->samplingRulesCache) {
-            return $this->samplingRulesCache;
-        }
-
-        $this->samplingRulesCache = [];
-
-        $parsed = \json_decode($this->stringValue('trace.sampling.rules'), true);
-        if (false === $parsed) {
-            $parsed = [];
-        }
-
-        // We do a proper parsing here to make sure that once the sampling rules leave this method
-        // they are always properly defined.
-        if (is_array($parsed)) {
-            foreach ($parsed as $rule) {
-                if (!is_array($rule) || !isset($rule['sample_rate'])) {
-                    continue;
-                }
-                $service = isset($rule['service']) ? strval($rule['service']) : '.*';
-                $name = isset($rule['name']) ? strval($rule['name']) : '.*';
-                $rate = isset($rule['sample_rate']) ? floatval($rule['sample_rate']) : 1.0;
-                $this->samplingRulesCache[] = [
-                    'service' => $service,
-                    'name' => $name,
-                    'sample_rate' => $rate,
-                ];
-            }
-        }
-
-        return $this->samplingRulesCache;
-    }
-
-    /**
-     * Whether or not a specific integration is enabled.
-     *
-     * @param string $name
-     * @return bool
-     */
-    public function isIntegrationEnabled($name)
-    {
-        if (function_exists('ddtrace_config_integration_enabled')) {
-            return \ddtrace_config_integration_enabled($name);
-        }
-        return $this->isEnabled() && !$this->inArray('integrations.disabled', $name);
-    }
-
-    /**
-     * Returns the global tags to be set on all spans.
-     */
-    public function getGlobalTags()
-    {
-        return $this->associativeStringArrayValue('tags') ?: $this->associativeStringArrayValue('trace.global.tags');
-    }
-
-    /**
-     * Returns the service mapping.
-     */
-    public function getServiceMapping()
-    {
-        // We use the format 'service.mapping' instead of 'trace.service.mapping' for consistency
-        // with java naming pattern for this very same config: DD_SERVICE_MAPPING
-        return $this->associativeStringArrayValue('service.mapping');
-    }
-
-    /**
-     * Append hostname as a root span tag
-     *
-     * @return bool
-     */
-    public function isHostnameReportingEnabled()
-    {
-        return $this->boolValue('trace.report.hostname', false);
-    }
-
-    /**
-     * Use normalized URL as resource name
-     *
-     * @return bool
-     */
-    public function isURLAsResourceNameEnabled()
-    {
-        return $this->boolValue('trace.url.as.resource.names.enabled', true);
-    }
-
-    /**
-     * Set URL hostname as service name
-     *
-     * @return bool
-     */
-    public function isHttpClientSplitByDomain()
-    {
-        return $this->boolValue('trace.http.client.split.by.domain', false);
-    }
-
-    /**
-     * The name of the application.
-     *
-     * @param string $default
-     * @return string
-     */
-    public function appName($default = '')
-    {
-        $service = $this->stringValue('service', null);
-        $service = $service ?: $this->stringValue('service.name', null);
-        $service = $service ?: $default;
-        return $service;
-    }
-
-    /**
-     * The version of the application.
-     * A return value of null indicates the version is not set.
-     *
-     * @return string|null
-     */
-    public function getServiceVersion()
-    {
-        // Using the env `DD_VERSION` for consistency with other tracers.
-        return $this->stringValue('version', null);
-    }
-
-    /**
-     * The environment for the application.
-     * A return value of null indicates the env is not set.
-     *
-     * @return string|null
-     */
-    public function getEnv()
-    {
-        // Using the env `DD_ENV` for consistency with other tracers.
-        return $this->stringValue('env', null);
-    }
-}
diff --git a/src/api/Configuration/AbstractConfiguration.php b/src/api/Configuration/AbstractConfiguration.php
deleted file mode 100644
index 0c4a85410b..0000000000
--- a/src/api/Configuration/AbstractConfiguration.php
+++ /dev/null
@@ -1,104 +0,0 @@
-<?php
-
-namespace DDTrace\Configuration;
-
-/**
- * DDTrace abstract configuration class.
- */
-abstract class AbstractConfiguration implements Registry
-{
-    /**
-     * @var static
-     */
-    private static $instance;
-
-    /**
-     * @var EnvVariableRegistry
-     */
-    protected $registry;
-
-    final protected function __construct()
-    {
-        $this->registry = new EnvVariableRegistry();
-    }
-
-    /**
-     * Returns the singleton configuration instance.
-     *
-     * @return static
-     */
-    public static function get()
-    {
-        if (self::$instance === null) {
-            self::$instance = new static();
-        }
-
-        return self::$instance;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function stringValue($key, $default = '')
-    {
-        return $this->registry->stringValue($key, $default);
-    }
-
-    /**
-     * {@inheritdoc}
-     *
-     * Allows users to access configuration properties by name instead of calling explicit methods.
-     */
-    public function boolValue($key, $default)
-    {
-        return $this->registry->boolValue($key, $default);
-    }
-
-    /**
-     * {@inheritdoc}
-     *
-     * Returns a floating point value from the registry.
-     */
-    public function floatValue($key, $default, $min = null, $max = null)
-    {
-        return $this->registry->floatValue($key, $default, $min, $max);
-    }
-
-    /**
-     * {@inheritdoc}
-     *
-     * Reads a configuration property into an associative string => string array.
-     */
-    public function associativeStringArrayValue($key)
-    {
-        return $this->registry->associativeStringArrayValue($key);
-    }
-
-    /**
-     * {@inheritdoc}
-     *
-     * Allows users to access configuration properties by name instead of calling explicit methods.
-     */
-    public function inArray($key, $name)
-    {
-        return $this->registry->inArray($key, $name);
-    }
-
-    /**
-     * Replaces the singleton instance.
-     *
-     * @param AbstractConfiguration $configuration
-     */
-    public static function replace(AbstractConfiguration $configuration)
-    {
-        self::$instance = $configuration;
-    }
-
-    /**
-     * Clear the singleton instance.
-     */
-    public static function clear()
-    {
-        self::$instance = null;
-    }
-}
diff --git a/src/api/Configuration/EnvVariableRegistry.php b/src/api/Configuration/EnvVariableRegistry.php
deleted file mode 100644
index 9bcb6d7604..0000000000
--- a/src/api/Configuration/EnvVariableRegistry.php
+++ /dev/null
@@ -1,204 +0,0 @@
-<?php
-
-namespace DDTrace\Configuration;
-
-/**
- * Registry that holds configuration properties and that is able to recover configuration values from environment
- * variables.
- */
-class EnvVariableRegistry implements Registry
-{
-    /**
-     * @var array
-     */
-    private $registry;
-
-    /**
-     * @var string
-     */
-    private $prefix;
-
-    /**
-     * @param string $prefix
-     */
-    public function __construct($prefix = 'DD_')
-    {
-        $this->prefix = $prefix;
-        $this->registry = [];
-    }
-
-    private function readEnvOrIni($name)
-    {
-        $ini_name = strtolower(strtr($name, [
-            "DD_TRACE_" => "datadog.trace.",
-            "DD_" => "datadog.",
-        ]));
-        $ini = ini_get($ini_name);
-        if ($ini !== false) {
-            return $ini;
-        }
-        return \getenv($name);
-    }
-
-    /**
-     * Return an env variable that starts with "DD_".
-     *
-     * @param string $key
-     * @return string|null
-     */
-    protected function get($key)
-    {
-        $value = $this->readEnvOrIni($this->convertKeyToEnvVariableName($key));
-        if (false === $value) {
-            return null;
-        }
-        return trim($value);
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function stringValue($key, $default)
-    {
-        if (isset($this->registry[$key])) {
-            return $this->registry[$key];
-        }
-        $value = $this->get($key);
-        if (null !== $value) {
-            return $this->registry[$key] = $value;
-        } else {
-            return $this->registry[$key] = $default;
-        }
-        return $this->registry[$key];
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function boolValue($key, $default)
-    {
-        if (isset($this->registry[$key])) {
-            return $this->registry[$key];
-        }
-
-        $value = $this->get($key);
-        if (null === $value) {
-            return $default;
-        }
-
-        $value = strtolower($value);
-        if ($value === '1' || $value === 'true') {
-            $this->registry[$key] = true;
-        } elseif ($value === '0' || $value === 'false') {
-            $this->registry[$key] = false;
-        } else {
-            $this->registry[$key] = $default;
-        }
-
-        return $this->registry[$key];
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function floatValue($key, $default, $min = null, $max = null)
-    {
-        if (!isset($this->registry[$key])) {
-            $value = $this->get($key);
-            $value = $value === null ? "" : strtolower($value);
-            if (is_numeric($value)) {
-                $floatValue = (float)$value;
-            } else {
-                $floatValue = (float)$default;
-            }
-
-            if (null !== $min && $floatValue < $min) {
-                $floatValue = $min;
-            }
-
-            if (null !== $max && $floatValue > $max) {
-                $floatValue = $max;
-            }
-
-            $this->registry[$key] = $floatValue;
-        }
-
-        return $this->registry[$key];
-    }
-
-    /**
-     * Given a string like 'key1:value1,key2:value2', it returns an associative array
-     * ['key1'=> 'value1', 'key2'=> 'value2']
-     *
-     * @param string $key
-     * @return string[]
-     */
-    public function associativeStringArrayValue($key)
-    {
-        if (isset($this->registry[$key])) {
-            return $this->registry[$key];
-        }
-
-        $default = [];
-        $value = $this->get($key);
-
-        if (null === $value) {
-            return $default;
-        }
-
-        // For now we provide no escaping
-        $this->registry[$key] = [];
-        $elements = explode(',', $value);
-        foreach ($elements as $element) {
-            $keyAndValue = explode(':', $element);
-
-            if (count($keyAndValue) !== 2) {
-                continue;
-            }
-
-            $keyFragment = trim($keyAndValue[0]);
-            $valueFragment = trim($keyAndValue[1]);
-
-            if (empty($keyFragment)) {
-                continue;
-            }
-
-            $this->registry[$key][$keyFragment] = $valueFragment;
-        }
-
-        return $this->registry[$key];
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function inArray($key, $name)
-    {
-        if (!isset($this->registry[$key])) {
-            $value = $this->get($key);
-            if (null !== $value) {
-                $disabledIntegrations = explode(',', $value);
-                $this->registry[$key] = array_map(function ($entry) {
-                    return strtolower(trim($entry));
-                }, $disabledIntegrations);
-            } else {
-                $this->registry[$key] = [];
-            }
-        }
-
-        return in_array(strtolower($name), $this->registry[$key], true);
-    }
-
-    /**
-     * Given a dot separated key, it converts it to an expected variable name.
-     *
-     * e.g.: 'distributed_tracing' -> 'DD_DISTRIBUTED_TRACING'
-     *
-     * @param string $key
-     * @return string
-     */
-    private function convertKeyToEnvVariableName($key)
-    {
-        return $this->prefix . strtoupper(str_replace('.', '_', trim($key)));
-    }
-}
diff --git a/src/api/Configuration/Registry.php b/src/api/Configuration/Registry.php
deleted file mode 100644
index eafa80d9f8..0000000000
--- a/src/api/Configuration/Registry.php
+++ /dev/null
@@ -1,56 +0,0 @@
-<?php
-
-namespace DDTrace\Configuration;
-
-/**
- * Registry interface for configuration stores.
- */
-interface Registry
-{
-    /**
-     * Extract a string configuration value, providing a default if the value has not been configured.
-     *
-     * @param string $key
-     * @param string $default
-     * @return string
-     */
-    public function stringValue($key, $default);
-
-    /**
-     * Extract a boolean configuration value, providing a default if the value has not been configured.
-     *
-     * @param string $key
-     * @param bool $default
-     * @return bool
-     */
-    public function boolValue($key, $default);
-
-    /**
-     * Extract a float configuration value, providing a default if the value has not been configured.
-     *
-     * @param string $key
-     * @param float $default
-     * @param float|null $min
-     * @param float|null $max
-     * @return float
-     */
-    public function floatValue($key, $default, $min = null, $max = null);
-
-    /**
-     * Given a string like 'key1:value1,key2:value2', it returns an associative array
-     * ['key1'=> 'value1', 'key2'=> 'value2']
-     *
-     * @param string $key
-     * @return string[]
-     */
-    public function associativeStringArrayValue($key);
-
-    /**
-     * Returns whether or not a given case-insensitive name is contained in a configuration property.
-     *
-     * @param string $key
-     * @param string $name
-     * @return bool
-     */
-    public function inArray($key, $name);
-}
diff --git a/src/api/Data/Span.php b/src/api/Data/Span.php
index abbeb90515..0b3835effa 100644
--- a/src/api/Data/Span.php
+++ b/src/api/Data/Span.php
@@ -2,7 +2,6 @@
 
 namespace DDTrace\Data;
 
-use DDTrace\Time;
 use DDTrace\Data\SpanContext as SpanContextData;
 use DDTrace\Contracts\Span as SpanInterface;
 
diff --git a/tests/Composer/app/index.php b/tests/Composer/app/index.php
index e7e4ec22de..2f747e0d4c 100644
--- a/tests/Composer/app/index.php
+++ b/tests/Composer/app/index.php
@@ -38,11 +38,6 @@
         $span->setTag(Tag::SPAN_TYPE, Type::MEMCACHED);
         $scope->close();
 
-        /*
-        * Using Configuration class from 'api' (which no longer exists in the 'src')
-        */
-        Configuration::get()->appName('default');
-
         /*
         * Using Logger class which is defined in both 'src' AND 'api'
         */
diff --git a/tests/OpenTracer1Unit/TracerTest.php b/tests/OpenTracer1Unit/TracerTest.php
index c3195f8198..c192e6077d 100644
--- a/tests/OpenTracer1Unit/TracerTest.php
+++ b/tests/OpenTracer1Unit/TracerTest.php
@@ -9,7 +9,6 @@
 use DDTrace\Tag;
 use DDTrace\Tests\DebugTransport;
 use DDTrace\Tests\Common\BaseTestCase;
-use DDTrace\Time;
 use DDTrace\Transport\Noop as NoopTransport;
 use OpenTracing\GlobalTracer;
 use OpenTracing\Formats;
@@ -85,7 +84,7 @@ public function testCreateSpanWithExpectedValues()
     {
         $tracer = Tracer::make(new NoopTransport());
         $rootSpan = $tracer->startSpan("rootSpan");
-        $startTime = Time::now();
+        $startTime = 12345;
         $span = $tracer
             ->startSpan(self::OPERATION_NAME, [
                 'tags' => [
diff --git a/tests/OpenTracerUnit/SpanTest.php b/tests/OpenTracerUnit/SpanTest.php
index afbfec02f7..83ce510036 100644
--- a/tests/OpenTracerUnit/SpanTest.php
+++ b/tests/OpenTracerUnit/SpanTest.php
@@ -4,11 +4,9 @@
 
 use DDTrace\OpenTracer\Span;
 use DDTrace\Span as DDSpan;
-use DDTrace\SpanData;
 use DDTrace\SpanContext as DDSpanContext;
 use DDTrace\Tag;
 use DDTrace\Tests\Common\BaseTestCase;
-use DDTrace\Time;
 use Exception;
 
 final class SpanTest extends BaseTestCase
diff --git a/tests/OpenTracerUnit/TracerTest.php b/tests/OpenTracerUnit/TracerTest.php
index c221a6d15e..803baa1018 100644
--- a/tests/OpenTracerUnit/TracerTest.php
+++ b/tests/OpenTracerUnit/TracerTest.php
@@ -9,7 +9,6 @@
 use DDTrace\Tag;
 use DDTrace\Tests\DebugTransport;
 use DDTrace\Tests\Common\BaseTestCase;
-use DDTrace\Time;
 use DDTrace\Transport\Noop as NoopTransport;
 use OpenTracing\GlobalTracer;
 use OpenTracing\Formats;
@@ -91,7 +90,7 @@ public function testCreateSpanWithEnvAndVersionPrecedence()
     public function testCreateSpanWithExpectedValues()
     {
         $tracer = Tracer::make(new NoopTransport());
-        $startTime = Time::now();
+        $startTime = 12345;
         $span = $tracer
             ->startSpan(self::OPERATION_NAME, [
                 'tags' => [
diff --git a/tests/Unit/TimeTest.php b/tests/Unit/TimeTest.php
deleted file mode 100644
index 87e6140c1e..0000000000
--- a/tests/Unit/TimeTest.php
+++ /dev/null
@@ -1,36 +0,0 @@
-<?php
-
-namespace DDTrace\Tests;
-
-use DDTrace\Tests\Common\BaseTestCase;
-use DDTrace\Time;
-
-final class TimeTest extends BaseTestCase
-{
-    public function testNowHasTheExpectedLength()
-    {
-        $now = Time::now();
-        $this->assertEquals(16, strlen((string) $now));
-    }
-
-    /**
-     * @dataProvider microtimeProvider
-     */
-    public function testIsValidHasTheExpectedOutput($microtime, $isValid)
-    {
-        $this->assertEquals($isValid, Time::isValid($microtime));
-    }
-
-    public function microtimeProvider()
-    {
-        return [
-            [Time::now(), true],
-            [1234567890123456, true],
-            [123456789012345, false],
-            ['1234567890123456', false],
-            ['123456789012345', false],
-            ['123456789012345a', false],
-            ['abcdefgh12345678', false]
-        ];
-    }
-}
diff --git a/tests/Unit/TracerTest.php b/tests/Unit/TracerTest.php
index fb18059982..3494550853 100644
--- a/tests/Unit/TracerTest.php
+++ b/tests/Unit/TracerTest.php
@@ -7,7 +7,6 @@
 use DDTrace\SpanContext;
 use DDTrace\Tag;
 use DDTrace\Tests\DebugTransport;
-use DDTrace\Time;
 use DDTrace\Tracer;
 use DDTrace\Transport\Noop as NoopTransport;
 use DDTrace\Tests\Common\BaseTestCase;
@@ -52,7 +51,7 @@ public function testCreateSpanSuccessWithExpectedValues()
     {
         $tracer = new Tracer(new NoopTransport());
         $tracer->startRootSpan('foo'); // setting start_time not allowed on internal root span
-        $startTime = Time::now();
+        $startTime = 12345;
         $span = $tracer->startSpan(self::OPERATION_NAME, [
             'tags' => [
                 self::TAG_KEY => self::TAG_VALUE
diff --git a/tests/api/Unit/Configuration/EnvVariableRegistryTest.php b/tests/api/Unit/Configuration/EnvVariableRegistryTest.php
deleted file mode 100644
index ef21eebe79..0000000000
--- a/tests/api/Unit/Configuration/EnvVariableRegistryTest.php
+++ /dev/null
@@ -1,196 +0,0 @@
-<?php
-
-namespace DDTrace\Tests\Api\Unit\Configuration;
-
-use DDTrace\Configuration\EnvVariableRegistry;
-use DDTrace\Tests\Common\BaseTestCase;
-
-final class EnvVariableRegistryTest extends BaseTestCase
-{
-    protected function ddSetUp()
-    {
-        parent::ddSetUp();
-        self::putenv('DD_SOME_TEST_PARAMETER');
-        self::putenv('DD_CUSTOM_PREFIX_SOME_TEST_PARAMETER');
-    }
-
-    public function testPrefixDefaultToDD()
-    {
-        self::putenv('DD_SOME_TEST_PARAMETER=bar');
-        $registry = new EnvVariableRegistry();
-        $this->assertSame('bar', $registry->stringValue('some.test.parameter', 'foo'));
-    }
-
-    public function testPrefixCanBeCustomized()
-    {
-        self::putenv('DD_CUSTOM_PREFIX_SOME_TEST_PARAMETER=bar');
-        $registry = new EnvVariableRegistry('DD_CUSTOM_PREFIX_');
-        $this->assertSame('bar', $registry->stringValue('some.test.parameter', 'foo'));
-    }
-
-    public function testStringFromEnv()
-    {
-        self::putenv('DD_SOME_TEST_PARAMETER=bar');
-        $registry = new EnvVariableRegistry();
-        $this->assertSame('bar', $registry->stringValue('some.test.parameter', 'foo'));
-    }
-
-    public function testStringWillFallbackToDefault()
-    {
-        $registry = new EnvVariableRegistry();
-        $this->assertSame('foo', $registry->stringValue('some.test.parameter', 'foo'));
-    }
-
-    public function testTrueValueWhenEnvNotSet()
-    {
-        $registry = new EnvVariableRegistry();
-        $this->assertTrue($registry->boolValue('some.test.parameter', true));
-    }
-
-    public function testFalseValueWhenEnvNotSet()
-    {
-        $registry = new EnvVariableRegistry();
-        $this->assertFalse($registry->boolValue('some.test.parameter', false));
-    }
-
-    public function testBoolValueTrueEnvSetWord()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=tRuE   ');
-        $this->assertTrue($registry->boolValue('some.test.parameter', false));
-    }
-
-    public function testBoolValueTrueEnvSetNumber()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=1   ');
-        $this->assertTrue($registry->boolValue('some.test.parameter', false));
-    }
-
-    public function testBoolValueFalseEnvSetWord()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=fAlSe   ');
-        $this->assertFalse($registry->boolValue('some.test.parameter', true));
-    }
-
-    public function testBoolValueFalseEnvSetNumber()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=0   ');
-        $this->assertFalse($registry->boolValue('some.test.parameter', true));
-    }
-
-    public function testFloatValueProvided()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=0.7   ');
-        $this->assertSame(0.7, $registry->floatValue('some.test.parameter', 1));
-    }
-
-    public function testFloatValueNot()
-    {
-        $registry = new EnvVariableRegistry();
-        $this->assertSame(1.0, $registry->floatValue('some.test.parameter', 1));
-    }
-
-    public function testFloatValueAlwaysConvertedToFloat()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=1   ');
-        $this->assertEquals(1.0, $registry->floatValue('some.test.parameter', 1));
-    }
-
-    public function testFloatValueOverMax()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=10000   ');
-        $this->assertEquals(1.0, $registry->floatValue('some.test.parameter', 1, 0, 1));
-    }
-
-    public function testFloatValueBelowMin()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=0   ');
-        $this->assertEquals(1.0, $registry->floatValue('some.test.parameter', 1, 1, 2));
-    }
-
-    public function testInArrayNotSet()
-    {
-        $registry = new EnvVariableRegistry();
-        $this->assertFalse($registry->inArray('some.test.parameter', 'name'));
-    }
-
-    public function testInArraySet()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=value1,value2');
-        $this->assertTrue($registry->inArray('some.test.parameter', 'value1'));
-        $this->assertTrue($registry->inArray('some.test.parameter', 'value2'));
-        $this->assertFalse($registry->inArray('some.test.parameter', 'value3'));
-    }
-
-    public function testInArrayCaseInsensitive()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER=vAlUe1,VaLuE2');
-        $this->assertTrue($registry->inArray('some.test.parameter', 'value1'));
-        $this->assertTrue($registry->inArray('some.test.parameter', 'value2'));
-        $this->assertFalse($registry->inArray('some.test.parameter', 'value3'));
-    }
-
-    public function testInArrayWhiteSpaceBetweenDefinitions()
-    {
-        $registry = new EnvVariableRegistry();
-        self::putenv('DD_SOME_TEST_PARAMETER= value1    ,     value2     ');
-        $this->assertTrue($registry->inArray('some.test.parameter', 'value1'));
-        $this->assertTrue($registry->inArray('some.test.parameter', 'value2'));
-        $this->assertFalse($registry->inArray('some.test.parameter', 'value3'));
-    }
-
-    public function testAssociativeStringArrayNotPersistingDefaultValue()
-    {
-        $registry = new EnvVariableRegistry();
-        $this->assertSame([], $registry->associativeStringArrayValue('some.test.parameter'));
-
-        self::putenv('DD_SOME_TEST_PARAMETER=key:value');
-
-        $this->assertSame(['key' => 'value'], $registry->associativeStringArrayValue('some.test.parameter'));
-    }
-
-    /**
-     * @dataProvider associativeStringArrayDataProvider
-     * @param string|null $env
-     * @param string $expected
-     */
-    public function testAssociativeStringArray($env, $expected)
-    {
-        if (null !== $env) {
-            self::putenv('DD_SOME_TEST_PARAMETER=' . $env);
-        }
-        $registry = new EnvVariableRegistry();
-        $this->assertSame($expected, $registry->associativeStringArrayValue('some.test.parameter'));
-    }
-
-    public function associativeStringArrayDataProvider()
-    {
-        return [
-
-            'env not set' => [null, []],
-
-            'empty string' => ['', []],
-
-            'only key' => ['only_key', []],
-
-            'empty key' => [':value', []],
-
-            'one value' => ['  key:   value    ', ['key' => 'value']],
-
-            'multiple values' => ['  key1:   value1  , key2 :value2  ', ['key1' => 'value1', 'key2' => 'value2']],
-
-            'preserves case' => ['  kEy1:   vAlUe1  ', ['kEy1' => 'vAlUe1']],
-
-            'tolerant to errors' => ['  kEy1:   vAlUe1 : wrong  ', []],
-        ];
-    }
-}
diff --git a/tests/api/Unit/ConfigurationTest.php b/tests/api/Unit/ConfigurationTest.php
deleted file mode 100644
index 8fb5ae03d5..0000000000
--- a/tests/api/Unit/ConfigurationTest.php
+++ /dev/null
@@ -1,385 +0,0 @@
-<?php
-
-namespace DDTrace\Tests\Api\Unit;
-
-use DDTrace\Configuration;
-use DDTrace\Tests\Common\BaseTestCase;
-
-final class ConfigurationTest extends BaseTestCase
-{
-    const INTEGRATION_ERROR = <<<'EOD'
-
-This could mean that a new integration was added in userland but was not added
-to the `ddtrace_integration_name` enum and the `ddtrace_integrations` array
-found in integrations.{h,c}. Integration-specific config for this integration will
-fall back to the defaults if they have not been added at the extension level.
-EOD;
-
-    protected function ddSetUp()
-    {
-        parent::ddSetUp();
-        Configuration::clear();
-        $this->cleanUpEnvs();
-    }
-
-    protected function ddTearDown()
-    {
-        $this->cleanUpEnvs();
-        Configuration::clear();
-        parent::ddTearDown();
-    }
-
-    private function cleanUpEnvs()
-    {
-        self::putenv('DD_DISTRIBUTED_TRACING');
-        self::putenv('DD_ENV');
-        self::putenv('DD_SERVICE_MAPPING');
-        self::putenv('DD_SERVICE');
-        self::putenv('DD_TAGS');
-        self::putenv('DD_TRACE_ANALYTICS_ENABLED');
-        self::putenv('DD_TRACE_DEBUG');
-        self::putenv('DD_TRACE_ENABLED');
-        self::putenv('DD_TRACE_SAMPLE_RATE');
-        self::putenv('DD_TRACE_SAMPLING_RULES');
-        self::putenv('DD_TRACE_SLIM_ENABLED');
-        self::putenv('DD_TRACE_PDO_ENABLED');
-        self::putenv('DD_VERSION');
-    }
-
-    public function testTracerEnabledByDefault()
-    {
-        $this->assertTrue(Configuration::get()->isEnabled());
-    }
-
-    public function testTracerDisabled()
-    {
-        $this->putEnvAndReloadConfig(['DD_TRACE_ENABLED=false']);
-        $this->assertFalse(Configuration::get()->isEnabled());
-    }
-
-    public function testDebugModeDisabledByDefault()
-    {
-        $this->assertFalse(Configuration::get()->isDebugModeEnabled());
-    }
-
-    public function testDebugModeCanBeEnabled()
-    {
-        $this->putEnvAndReloadConfig(['DD_TRACE_DEBUG=true']);
-        $this->assertTrue(Configuration::get()->isDebugModeEnabled());
-    }
-
-    public function testDistributedTracingEnabledByDefault()
-    {
-        $this->assertTrue(Configuration::get()->isDistributedTracingEnabled());
-    }
-
-    public function testDistributedTracingDisabled()
-    {
-        $this->putEnvAndReloadConfig(['DD_DISTRIBUTED_TRACING=false']);
-        $this->assertFalse(Configuration::get()->isDistributedTracingEnabled());
-    }
-
-    public function testAllIntegrationsEnabledByDefault()
-    {
-        $this->assertTrue(Configuration::get()->isIntegrationEnabled('pdo'));
-    }
-
-    public function testIntegrationsDisabled()
-    {
-        $this->putEnvAndReloadConfig(['DD_TRACE_PDO_ENABLED=false', 'DD_TRACE_SLIM_ENABLED=false']);
-        $this->assertFalse(Configuration::get()->isIntegrationEnabled('pdo'));
-        $this->assertFalse(Configuration::get()->isIntegrationEnabled('slim'));
-        $this->assertTrue(Configuration::get()->isIntegrationEnabled('mysqli'));
-    }
-
-    public function testIntegrationsDisabledIfGlobalDisabled()
-    {
-        $this->putEnvAndReloadConfig(['DD_TRACE_PDO_ENABLED=false', 'DD_TRACE_ENABLED=false']);
-        $this->assertFalse(Configuration::get()->isIntegrationEnabled('pdo'));
-        $this->assertFalse(Configuration::get()->isIntegrationEnabled('mysqli'));
-    }
-
-    public function testAllIntegrationsEnabledToggleConfig()
-    {
-        $integrations = self::getIntegrationsUpper();
-        foreach ($integrations as $integration) {
-            $this->putEnvAndReloadConfig(["DD_TRACE_{$integration}_ENABLED=false"]);
-
-            $lower = strtolower($integration);
-            $error = "'{$lower}' was expected to be disabled." . self::INTEGRATION_ERROR;
-            self::assertFalse(Configuration::get()->isIntegrationEnabled($lower), $error);
-
-            // Reset
-            self::putenv("DD_TRACE_{$integration}_ENABLED");
-        }
-
-        // Make sure we're not testing the default fallback
-        self::assertTrue(Configuration::get()->isIntegrationEnabled('foo_invalid'));
-    }
-
-    private static function getIntegrationsUpper()
-    {
-        $dirs = glob(__DIR__ . '/../../src/DDTrace/Integrations/*', GLOB_ONLYDIR);
-        return array_map(function ($entry) {
-            return strtoupper(substr($entry, strrpos($entry, '/') + 1));
-        }, $dirs);
-    }
-
-    public function testServiceName()
-    {
-        $this->putEnvAndReloadConfig(['DD_SERVICE']);
-
-        $this->assertSame('__default__', Configuration::get()->appName('__default__'));
-
-        $this->putEnvAndReloadConfig(['DD_SERVICE=my_app']);
-        Configuration::clear();
-        $this->assertSame('my_app', Configuration::get()->appName('__default__'));
-    }
-
-    public function testAnalyticsDisabledByDefault()
-    {
-        $this->assertFalse(Configuration::get()->isAnalyticsEnabled());
-    }
-
-    public function testAnalyticsCanBeGloballyEnabled()
-    {
-        $this->putEnvAndReloadConfig(['DD_TRACE_ANALYTICS_ENABLED=true']);
-        $this->assertTrue(Configuration::get()->isAnalyticsEnabled());
-    }
-
-    /**
-     * @dataProvider dataProviderTestTraceSamplingRules
-     * @param mixed $rules
-     * @param array $expected
-     */
-    public function testTraceSamplingRules($rules, $expected)
-    {
-        if (false !== $rules) {
-            $this->putEnvAndReloadConfig(['DD_TRACE_SAMPLING_RULES=' . $rules]);
-        }
-
-        $this->assertSame($expected, Configuration::get()->getSamplingRules());
-    }
-
-    public function dataProviderTestTraceSamplingRules()
-    {
-        return [
-            'DD_TRACE_SAMPLING_RULES not defined' => [
-                false,
-                [],
-            ],
-            'DD_TRACE_SAMPLING_RULES empty string' => [
-                '',
-                [],
-            ],
-            'DD_TRACE_SAMPLING_RULES not a valid json' => [
-                '[a!}',
-                [],
-            ],
-            'DD_TRACE_SAMPLING_RULES empty array' => [
-                '[]',
-                [],
-            ],
-            'DD_TRACE_SAMPLING_RULES empty object' => [
-                '[{}]',
-                [],
-            ],
-            'DD_TRACE_SAMPLING_RULES only rate' => [
-                '[{"sample_rate": 0.3}]',
-                [
-                    [
-                        'service' => '.*',
-                        'name' => '.*',
-                        'sample_rate' => 0.3,
-                    ],
-                ],
-            ],
-            'DD_TRACE_SAMPLING_RULES service defined' => [
-                '[{"service": "my_service", "sample_rate": 0.3}]',
-                [
-                    [
-                        'service' => 'my_service',
-                        'name' => '.*',
-                        'sample_rate' => 0.3,
-                    ],
-                ],
-            ],
-            'DD_TRACE_SAMPLING_RULES named defined' => [
-                '[{"name": "my_name", "sample_rate": 0.3}]',
-                [
-                    [
-                        'service' => '.*',
-                        'name' => 'my_name',
-                        'sample_rate' => 0.3,
-                    ],
-                ],
-            ],
-            'DD_TRACE_SAMPLING_RULES multiple values keeps order' => [
-                '[{"name": "my_name", "sample_rate": 0.3}, {"service": "my_service", "sample_rate": 0.7}]',
-                [
-                    [
-                        'service' => '.*',
-                        'name' => 'my_name',
-                        'sample_rate' => 0.3,
-                    ],
-                    [
-                        'service' => 'my_service',
-                        'name' => '.*',
-                        'sample_rate' => 0.7,
-                    ],
-                ],
-            ],
-            'DD_TRACE_SAMPLING_RULES values converted to proper type' => [
-                '[{"name": 1, "sample_rate": "0.3"}]',
-                [
-                    [
-                        'service' => '.*',
-                        'name' => '1',
-                        'sample_rate' => 0.3,
-                    ],
-                ],
-            ],
-            'DD_TRACE_SAMPLING_RULES regex can be provided' => [
-                '[{"name": "^a.*b$", "sample_rate": 0.3}]',
-                [
-                    [
-                        'service' => '.*',
-                        'name' => '^a.*b$',
-                        'sample_rate' => 0.3,
-                    ],
-                ],
-            ],
-        ];
-    }
-
-    /**
-     * @dataProvider dataProviderTestTraceSampleRate
-     * @param mixed $envs
-     * @param float $expected
-     */
-    public function testTraceSampleRate($envs, $expected)
-    {
-        foreach ($envs as $env) {
-            $this->putEnvAndReloadConfig([$env]);
-        }
-
-        $this->assertEquals($expected, Configuration::get()->getSamplingRate());
-    }
-
-    public function dataProviderTestTraceSampleRate()
-    {
-        return [
-            'defaults to 1.0 when nothing is set' => [
-                [],
-                1.0,
-            ],
-            'DD_TRACE_SAMPLE_RATE can be set' => [
-                [
-                    'DD_TRACE_SAMPLE_RATE=0.7',
-                ],
-                0.7,
-            ],
-            // i.e. default sample rate: will be 1 then
-            'DD_TRACE_SAMPLE_RATE has a minimum of 0.0' => [
-                [
-                    'DD_TRACE_SAMPLE_RATE=-0.1',
-                ],
-                1,
-            ],
-            'DD_TRACE_SAMPLE_RATE has a maximum of 1.0' => [
-                [
-                    'DD_TRACE_SAMPLE_RATE=1.1',
-                ],
-                1.0,
-            ],
-        ];
-    }
-
-    /**
-     * @dataProvider dataProviderTestServiceMapping
-     * @param mixed $envs
-     * @param array $expected
-     */
-    public function testTraceServiceMapping($env, $expected)
-    {
-        if (false !== $env) {
-            $this->putEnvAndReloadConfig(["DD_SERVICE_MAPPING=$env"]);
-        }
-
-        $this->assertSame($expected, Configuration::get()->getServiceMapping());
-    }
-
-    public function dataProviderTestServiceMapping()
-    {
-        return [
-            'not set' => [
-                false,
-                [],
-            ],
-            'empty' => [
-                false,
-                [],
-            ],
-            'one service mapping' => [
-                'service1:service2',
-                [ 'service1' => 'service2' ],
-            ],
-            'multiple service mappings' => [
-                'service1:service2,service3:service4',
-                [ 'service1' => 'service2', 'service3' => 'service4' ],
-            ],
-            'tolerant to extra whitespace' => [
-                'service1 :    service2 ,         service3 : service4                    ',
-                [ 'service1' => 'service2', 'service3' => 'service4' ],
-            ],
-        ];
-    }
-
-    public function testEnv()
-    {
-        $this->putEnvAndReloadConfig(['DD_ENV=my-env']);
-        $this->assertSame('my-env', Configuration::get()->getEnv());
-    }
-
-    public function testEnvNotSet()
-    {
-        $this->putEnvAndReloadConfig(['DD_ENV']);
-        $this->assertEmpty(Configuration::get()->getEnv());
-    }
-
-    public function testVersion()
-    {
-        $this->putEnvAndReloadConfig(['DD_VERSION=1.2.3']);
-        $this->assertSame('1.2.3', Configuration::get()->getServiceVersion());
-    }
-
-    public function testVersionNotSet()
-    {
-        $this->putEnvAndReloadConfig(['DD_VERSION']);
-        $this->assertEmpty(Configuration::get()->getServiceVersion());
-    }
-
-    public function testUriAsResourceNameEnabledDefault()
-    {
-        $this->assertTrue(Configuration::get()->isURLAsResourceNameEnabled());
-    }
-
-    public function testUriAsResourceNameCanBeDisabled()
-    {
-        $this->putEnvAndReloadConfig(['DD_TRACE_URL_AS_RESOURCE_NAMES_ENABLED=false']);
-        $this->assertFalse(Configuration::get()->isURLAsResourceNameEnabled());
-    }
-
-    public function testGlobalTags()
-    {
-        $this->putEnvAndReloadConfig(['DD_TAGS=key1:value1,key2:value2']);
-        $this->assertEquals(['key1' => 'value1', 'key2' => 'value2'], Configuration::get()->getGlobalTags());
-        $this->assertEquals(['key1' => 'value1', 'key2' => 'value2'], \dd_trace_env_config("DD_TAGS"));
-    }
-
-    public function testGlobalTagsWrongValueJustResultsInNoTags()
-    {
-        $this->putEnvAndReloadConfig(['DD_TAGS=wrong_key_value']);
-        $this->assertEquals([], Configuration::get()->getGlobalTags());
-    }
-}