refactor: add mongodb+srv tests to atlas connectivity tests

This simplifies how we test our many connectivity tests while also
adding a few new ones for `mongodb+srv` hosts. Specifically, it
converts the connectivity tests to a new "manual" style test using
mocha, and then merges many environment variables into a single
JSON blob.

NODE-2021

Author: mbroadst

.evergreen/config.yml

@@ -154,14 +154,23 @@ functions:
     - command: shell.exec
       type: test
       params:
-        working_dir: src
         silent: true
-        script: >
-          # DO NOT ECHO WITH XTRACE (which PREPARE_SHELL does)
+        working_dir: src
+        script: |
+          cat <<EOT > prepare_atlas_connectivity.sh
+          export ATLAS_CONNECTIVITY='${ATLAS_CONNECTIVITY}'
+          EOT
+    - command: shell.exec
+      type: test
+      params:
+        working_dir: src
+        script: |
+          # Disable xtrace (just in case it was accidentally set).
+          set +x
+          . ./prepare_atlas_connectivity.sh
+          rm -f ./prepare_atlas_connectivity.sh
 
-          NODE_LTS_NAME='${NODE_LTS_NAME}' ATLAS_REPL='${atlas_repl}' ATLAS_SHRD='${atlas_shrd}'
-          ATLAS_FREE='${atlas_free}' ATLAS_TLS11='${atlas_tls11}' ATLAS_TLS12='${atlas_tls12}' bash
-          ${PROJECT_DIRECTORY}/.evergreen/run-atlas-tests.sh
+          NODE_LTS_NAME='${NODE_LTS_NAME}' bash ${PROJECT_DIRECTORY}/.evergreen/run-atlas-tests.sh
 pre:
   - func: fetch source
   - func: prepare resources

.evergreen/config.yml.in

@@ -189,11 +189,23 @@ functions:
     - command: shell.exec
       type: test
       params:
-        working_dir: "src"
         silent: true
+        working_dir: "src"
         script: |
-          # DO NOT ECHO WITH XTRACE (which PREPARE_SHELL does)
-          NODE_LTS_NAME='${NODE_LTS_NAME}' ATLAS_REPL='${atlas_repl}' ATLAS_SHRD='${atlas_shrd}' ATLAS_FREE='${atlas_free}' ATLAS_TLS11='${atlas_tls11}' ATLAS_TLS12='${atlas_tls12}' bash ${PROJECT_DIRECTORY}/.evergreen/run-atlas-tests.sh
+          cat <<EOT > prepare_atlas_connectivity.sh
+          export ATLAS_CONNECTIVITY='${ATLAS_CONNECTIVITY}'
+          EOT
+    - command: shell.exec
+      type: test
+      params:
+        working_dir: "src"
+        script: |
+          # Disable xtrace (just in case it was accidentally set).
+          set +x
+          . ./prepare_atlas_connectivity.sh
+          rm -f ./prepare_atlas_connectivity.sh
+
+          NODE_LTS_NAME='${NODE_LTS_NAME}' bash ${PROJECT_DIRECTORY}/.evergreen/run-atlas-tests.sh
 
 pre:
   - func: "fetch source"

.evergreen/run-atlas-tests.sh

@@ -7,4 +7,4 @@ NODE_ARTIFACTS_PATH="${PROJECT_DIRECTORY}/node-artifacts"
 export NVM_DIR="${NODE_ARTIFACTS_PATH}/nvm"
 [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
 
-ATLAS_REPL="$ATLAS_REPL" ATLAS_SHRD="$ATLAS_SHRD" ATLAS_FREE="$ATLAS_FREE" ATLAS_TLS11="$ATLAS_TLS11" ATLAS_TLS12="$ATLAS_TLS12" npm run atlas
+npm run atlas

package.json

@@ -64,7 +64,7 @@
     "url": "https://github.com/mongodb/node-mongodb-native/issues"
   },
   "scripts": {
-    "atlas": "node ./test/tools/atlas_connectivity_tests.js",
+    "atlas": "mocha --opts '{}' ./test/manual/atlas_connectivity.test.js",
     "test": "npm run lint && mocha --recursive test/functional test/unit test/core",
     "test-nolint": "mocha --recursive test/functional test/unit test/core",
     "coverage": "istanbul cover mongodb-test-runner -- -t 60000 test/core test/unit test/functional",

test/manual/atlas_connectivity.test.js

@@ -0,0 +1,40 @@
+'use strict';
+const MongoClient = require('../..').MongoClient;
+
+describe('Atlas Connectivity', function() {
+  if (process.env.ATLAS_CONNECTIVITY == null) {
+    console.log(
+      'skipping atlas connectivity tests, ATLAS_CONNECTIVITY environment variable is not defined'
+    );
+
+    return;
+  }
+
+  const CONFIGS = JSON.parse(process.env.ATLAS_CONNECTIVITY);
+  Object.keys(CONFIGS).forEach(configName => {
+    context(configName, function() {
+      CONFIGS[configName].forEach(connectionString => {
+        const name = connectionString.indexOf('mongodb+srv') >= 0 ? 'mongodb+srv' : 'normal';
+        it(`${name} (unified)`, makeConnectionTest(connectionString, { useUnifiedTopology: true }));
+        it(`${name} (legacy)`, makeConnectionTest(connectionString, { useUnifiedTopology: false }));
+      });
+    });
+  });
+});
+
+function makeConnectionTest(connectionString, clientOptions) {
+  return function() {
+    const client = new MongoClient(connectionString, clientOptions);
+
+    return client
+      .connect()
+      .then(() => client.db('admin').command({ ismaster: 1 }))
+      .then(() =>
+        client
+          .db('test')
+          .collection('test')
+          .findOne({})
+      )
+      .then(() => client.close());
+  };
+}