Test utility for configuring test LDAP directories (#35)

Added test configuration framework and changed tests to use testDN.

.gitignore

@@ -8,4 +8,7 @@ tags
 .project
 *~
 .dart_tool/
-
+test/CONFIG.yaml
+test/CONFIG.YAML
+test/config.yaml
+test/Config.yaml

lib/src/dartdap/client/ldap_connection.dart

@@ -1012,7 +1012,7 @@ class LdapConnection {
 
       var result = await c.future;
 
-      if (_bindException) {
+      if (_bindException ?? false) {
         assert(result == null);
         throw _bindException;
       }

test/CONFIG-default.yaml

@@ -0,0 +1,12 @@
+# Default test configuration file
+#
+# To run tests using this configuration, make sure there is no file or symlink
+# called "CONFIG.yaml". See README.md for details.
+#
+# DO NOT CHANGE THIS FILE. To customize for a local test environment, create
+# a new configuration file and a "CONFIG.yaml" symlink to it.
+
+
+# This file deliberately does not define any directory configurations.
+# Tests that don't require an LDAP directory will still run, so it can
+# be used without requiring the tester to setup a test environment.

test/CONFIG-opendj.yaml

@@ -0,0 +1,26 @@
+# Example custom config file for special tests
+#
+# To run tests using this configuration, create a "CONFIG.yaml" symlink to it.
+# See README.md for details.
+
+directories:
+  populated-with-2000-users:
+    host: localhost
+    port: 1389
+    ssl: false
+    validate-certificate: false
+    bindDN: uid=admin
+    password: password
+    testDN: ou=people,ou=identities
+
+  directory-with-valid-certificates:
+    host: test-ldap.example.com
+    port: 636
+    ssl: true
+    validate-certificate: true  # perform normal X.509 validation
+    bindDN: uid=admin
+    password: password
+    testDN: ou=people,ou=identities
+
+# Note: this file needs a better name, since the tests can work with any
+# suitably configured LDAP directory, not just the OpenDJ implementation.

test/CONFIG-standard.yaml

@@ -0,0 +1,48 @@
+# Standard test config file
+#
+# To run tests using this configuration, create a "CONFIG.yaml" symlink to it.
+# See README.md for details.
+#
+# DO NOT CHANGE THIS FILE. To customize for a local test environment, create
+# a new configuration file and a "CONFIG.yaml" symlink to it.
+
+directories:
+  # Directory for tests with no special requirements
+  default:
+    host: "localhost"
+    port: 1389
+    ssl: false
+    bindDN: "cn=Manager,dc=example,dc=com"
+    password: "password"
+    testDN: "ou=testing,dc=example,dc=com"
+
+  # Directory for tests that require LDAP (must not use LDAPS, i.e. no TLS)
+  ldap:
+    host: "localhost"
+    port: 1389  # use a SSH tunnel to port 389 on the server
+    ssl: false
+    bindDN: "cn=Manager,dc=example,dc=com"
+    password: "password"
+    testDN: "ou=testing,dc=example,dc=com"
+
+  # Directory for tests that require LDAPS (must use LDAP over TLS)
+  ldaps:
+    host: "localhost"
+    port: 1636  # use a SSH tunnel to port 636 on the server
+    ssl: true
+    bindDN: "cn=Manager,dc=example,dc=com"
+    password: "password"
+    validate-certificate: false  # accepts self-signed certificates
+    testDN: "ou=testing,dc=example,dc=com"
+
+# logging:
+#   ldap.connection: INFO
+#   ldap.control: INFO
+#   ldap.recv.asn1: INFO
+#   ldap.recv.bytes: INFO
+#   ldap.recv.ldap: INFO
+#   ldap.recv: INFO
+#   ldap.send.bytes: INFO
+#   ldap.send.ldap: INFO
+#   ldap.send: INFO
+#   ldap: INFO