diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index fc78c3e8f8..e1d85d77c7 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -243,7 +243,7 @@ functions:
               "iam_auth_ec2_instance_profile" : "${iam_auth_ec2_instance_profile}"
           }
           EOF
-  run aws auth test with regular aws credentials:
+  setup aws env:
     - command: shell.exec
       type: test
       params:
@@ -252,6 +252,14 @@ functions:
           ${PREPARE_SHELL}
           cd ${DRIVERS_TOOLS}/.evergreen/auth_aws
           . ./activate_venv.sh
+          cd -
+  run aws auth test with regular aws credentials:
+    - command: shell.exec
+      type: test
+      params:
+        working_dir: src
+        script: |
+          cd ${DRIVERS_TOOLS}/.evergreen/auth_aws
           ${MONGODB_BINARIES}/mongo aws_e2e_regular_aws.js
     - command: shell.exec
       type: test
@@ -329,6 +337,9 @@ functions:
         working_dir: src
         silent: true
         script: |
+          cd ${DRIVERS_TOOLS}/.evergreen/auth_aws
+          ${MONGODB_BINARIES}/mongo --verbose aws_e2e_regular_aws.js
+          cd -
           cat <<EOF > "${PROJECT_DIRECTORY}/prepare_mongodb_aws.sh"
             export AWS_ACCESS_KEY_ID=${iam_auth_ecs_account}
             export AWS_SECRET_ACCESS_KEY=${iam_auth_ecs_secret_access_key}
@@ -348,6 +359,9 @@ functions:
         working_dir: src
         silent: true
         script: |
+          cd ${DRIVERS_TOOLS}/.evergreen/auth_aws
+          ${MONGODB_BINARIES}/mongo --verbose aws_e2e_assume_role.js
+          cd -
           cat <<'EOF' > "${PROJECT_DIRECTORY}/prepare_mongodb_aws.sh"
             export AWS_ACCESS_KEY_ID=$(jq -r '.AccessKeyId' ${DRIVERS_TOOLS}/.evergreen/auth_aws/creds.json)
             export AWS_SECRET_ACCESS_KEY=$(jq -r '.SecretAccessKey' ${DRIVERS_TOOLS}/.evergreen/auth_aws/creds.json)
@@ -387,7 +401,7 @@ functions:
 
           cat setup.js
           . ./activate_venv.sh
-          mongo --nodb setup.js aws_e2e_ecs.js
+          ${MONGODB_BINARIES}/mongo --nodb setup.js aws_e2e_ecs.js
   run-ocsp-test:
     - command: shell.exec
       type: test
@@ -1377,7 +1391,7 @@ tasks:
       - func: run-ocsp-test
         vars:
           OCSP_TLS_SHOULD_SUCCEED: 0
-  - name: aws-latest-auth-test
+  - name: aws-latest-auth-test-run-aws-auth-test-with-regular-aws-credentials
     commands:
       - func: install dependencies
       - func: bootstrap mongo-orchestration
@@ -1387,13 +1401,69 @@ tasks:
           ORCHESTRATION_FILE: auth-aws.json
           TOPOLOGY: server
       - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with regular aws credentials
+  - name: aws-latest-auth-test-run-aws-auth-test-with-assume-role-credentials
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: latest
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with assume role credentials
+  - name: aws-latest-auth-test-run-aws-auth-test-with-aws-EC2-credentials
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: latest
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with aws EC2 credentials
+  - name: aws-latest-auth-test-run-aws-auth-test-with-aws-credentials-as-environment-variables
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: latest
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with aws credentials as environment variables
+  - name: aws-latest-auth-test-run-aws-auth-test-with-aws-credentials-and-session-token-as-environment-variables
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: latest
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with aws credentials and session token as environment variables
+  - name: aws-latest-auth-test-run-aws-ECS-auth-test
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: latest
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws ECS auth test
-  - name: aws-4.4-auth-test
+  - name: aws-4.4-auth-test-run-aws-auth-test-with-regular-aws-credentials
     commands:
       - func: install dependencies
       - func: bootstrap mongo-orchestration
@@ -1403,11 +1473,67 @@ tasks:
           ORCHESTRATION_FILE: auth-aws.json
           TOPOLOGY: server
       - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with regular aws credentials
+  - name: aws-4.4-auth-test-run-aws-auth-test-with-assume-role-credentials
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: '4.4'
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with assume role credentials
+  - name: aws-4.4-auth-test-run-aws-auth-test-with-aws-EC2-credentials
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: '4.4'
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with aws EC2 credentials
+  - name: aws-4.4-auth-test-run-aws-auth-test-with-aws-credentials-as-environment-variables
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: '4.4'
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with aws credentials as environment variables
+  - name: aws-4.4-auth-test-run-aws-auth-test-with-aws-credentials-and-session-token-as-environment-variables
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: '4.4'
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws auth test with aws credentials and session token as environment variables
+  - name: aws-4.4-auth-test-run-aws-ECS-auth-test
+    commands:
+      - func: install dependencies
+      - func: bootstrap mongo-orchestration
+        vars:
+          VERSION: '4.4'
+          AUTH: auth
+          ORCHESTRATION_FILE: auth-aws.json
+          TOPOLOGY: server
+      - func: add aws auth variables to file
+      - func: setup aws env
       - func: run aws ECS auth test
   - name: run-checks
     tags:
@@ -1994,5 +2120,15 @@ buildvariants:
     expansions:
       NODE_LTS_NAME: carbon
     tasks:
-      - aws-latest-auth-test
-      - aws-4.4-auth-test
+      - aws-latest-auth-test-run-aws-auth-test-with-regular-aws-credentials
+      - aws-latest-auth-test-run-aws-auth-test-with-assume-role-credentials
+      - aws-latest-auth-test-run-aws-auth-test-with-aws-EC2-credentials
+      - aws-latest-auth-test-run-aws-auth-test-with-aws-credentials-as-environment-variables
+      - aws-latest-auth-test-run-aws-auth-test-with-aws-credentials-and-session-token-as-environment-variables
+      - aws-latest-auth-test-run-aws-ECS-auth-test
+      - aws-4.4-auth-test-run-aws-auth-test-with-regular-aws-credentials
+      - aws-4.4-auth-test-run-aws-auth-test-with-assume-role-credentials
+      - aws-4.4-auth-test-run-aws-auth-test-with-aws-EC2-credentials
+      - aws-4.4-auth-test-run-aws-auth-test-with-aws-credentials-as-environment-variables
+      - aws-4.4-auth-test-run-aws-auth-test-with-aws-credentials-and-session-token-as-environment-variables
+      - aws-4.4-auth-test-run-aws-ECS-auth-test
diff --git a/.evergreen/config.yml.in b/.evergreen/config.yml.in
index ea2a8b9ec5..5aa2c08f8e 100644
--- a/.evergreen/config.yml.in
+++ b/.evergreen/config.yml.in
@@ -274,7 +274,7 @@ functions:
           }
           EOF
 
-  "run aws auth test with regular aws credentials":
+  "setup aws env":
     - command: shell.exec
       type: test
       params:
@@ -283,6 +283,15 @@ functions:
           ${PREPARE_SHELL}
           cd ${DRIVERS_TOOLS}/.evergreen/auth_aws
           . ./activate_venv.sh
+          cd -
+
+  "run aws auth test with regular aws credentials":
+    - command: shell.exec
+      type: test
+      params:
+        working_dir: "src"
+        script: |
+          cd ${DRIVERS_TOOLS}/.evergreen/auth_aws
           ${MONGODB_BINARIES}/mongo aws_e2e_regular_aws.js
     - command: shell.exec
       type: test
@@ -363,6 +372,9 @@ functions:
         working_dir: "src"
         silent: true
         script: |
+          cd ${DRIVERS_TOOLS}/.evergreen/auth_aws
+          ${MONGODB_BINARIES}/mongo --verbose aws_e2e_regular_aws.js
+          cd -
           cat <<EOF > "${PROJECT_DIRECTORY}/prepare_mongodb_aws.sh"
             export AWS_ACCESS_KEY_ID=${iam_auth_ecs_account}
             export AWS_SECRET_ACCESS_KEY=${iam_auth_ecs_secret_access_key}
@@ -383,6 +395,9 @@ functions:
         working_dir: "src"
         silent: true
         script: |
+          cd ${DRIVERS_TOOLS}/.evergreen/auth_aws
+          ${MONGODB_BINARIES}/mongo --verbose aws_e2e_assume_role.js
+          cd -
           cat <<'EOF' > "${PROJECT_DIRECTORY}/prepare_mongodb_aws.sh"
             export AWS_ACCESS_KEY_ID=$(jq -r '.AccessKeyId' ${DRIVERS_TOOLS}/.evergreen/auth_aws/creds.json)
             export AWS_SECRET_ACCESS_KEY=$(jq -r '.SecretAccessKey' ${DRIVERS_TOOLS}/.evergreen/auth_aws/creds.json)
@@ -423,7 +438,7 @@ functions:
 
           cat setup.js
           . ./activate_venv.sh
-          mongo --nodb setup.js aws_e2e_ecs.js
+          ${MONGODB_BINARIES}/mongo --nodb setup.js aws_e2e_ecs.js
 
   "run-ocsp-test":
     - command: shell.exec
diff --git a/.evergreen/generate_evergreen_tasks.js b/.evergreen/generate_evergreen_tasks.js
index 037022480c..9fee00942a 100644
--- a/.evergreen/generate_evergreen_tasks.js
+++ b/.evergreen/generate_evergreen_tasks.js
@@ -296,10 +296,20 @@ OCSP_VERSIONS.forEach(VERSION => {
 const AWS_AUTH_TASKS = [];
 
 AWS_AUTH_VERSIONS.forEach(VERSION => {
-  const name = `aws-${VERSION}-auth-test`;
-  AWS_AUTH_TASKS.push(name);
-  TASKS.push({
-    name: name,
+  const name = (ex) => `aws-${VERSION}-auth-test-${ex.split(' ').join('-')}`;
+  // AWS_AUTH_TASKS.push(name);
+
+  const aws_funcs = [
+    { func: 'run aws auth test with regular aws credentials' },
+    { func: 'run aws auth test with assume role credentials' },
+    { func: 'run aws auth test with aws EC2 credentials' },
+    { func: 'run aws auth test with aws credentials as environment variables' },
+    { func: 'run aws auth test with aws credentials and session token as environment variables' },
+    { func: 'run aws ECS auth test' }
+  ];
+
+  const aws_tasks = aws_funcs.map(fn => ({
+    name: name(fn.func),
     commands: [
       { func: 'install dependencies' },
       {
@@ -312,14 +322,13 @@ AWS_AUTH_VERSIONS.forEach(VERSION => {
         }
       },
       { func: 'add aws auth variables to file' },
-      { func: 'run aws auth test with regular aws credentials' },
-      { func: 'run aws auth test with assume role credentials' },
-      { func: 'run aws auth test with aws EC2 credentials' },
-      { func: 'run aws auth test with aws credentials as environment variables' },
-      { func: 'run aws auth test with aws credentials and session token as environment variables' },
-      { func: 'run aws ECS auth test' }
+      { func: 'setup aws env' },
+      fn
     ]
-  });
+  }))
+
+  TASKS.push(...aws_tasks);
+  AWS_AUTH_TASKS.push(...aws_tasks.map(t => t.name))
 });
 
 const BUILD_VARIANTS = [];
diff --git a/lib/core/auth/mongo_credentials.js b/lib/core/auth/mongo_credentials.js
index 054e47d304..090969e540 100644
--- a/lib/core/auth/mongo_credentials.js
+++ b/lib/core/auth/mongo_credentials.js
@@ -49,16 +49,16 @@ class MongoCredentials {
     this.mechanism = options.mechanism || 'default';
     this.mechanismProperties = options.mechanismProperties || {};
 
-    if (this.mechanism.match(/MONGODB-AWS/i)) {
-      if (this.username == null && process.env.AWS_ACCESS_KEY_ID) {
+    if (/MONGODB-AWS/i.test(this.mechanism)) {
+      if (!this.username && process.env.AWS_ACCESS_KEY_ID) {
         this.username = process.env.AWS_ACCESS_KEY_ID;
       }
 
-      if (this.password == null && process.env.AWS_SECRET_ACCESS_KEY) {
+      if (!this.password && process.env.AWS_SECRET_ACCESS_KEY) {
         this.password = process.env.AWS_SECRET_ACCESS_KEY;
       }
 
-      if (this.mechanismProperties.AWS_SESSION_TOKEN == null && process.env.AWS_SESSION_TOKEN) {
+      if (!this.mechanismProperties.AWS_SESSION_TOKEN && process.env.AWS_SESSION_TOKEN) {
         this.mechanismProperties.AWS_SESSION_TOKEN = process.env.AWS_SESSION_TOKEN;
       }
     }
@@ -90,7 +90,7 @@ class MongoCredentials {
    */
   resolveAuthMechanism(ismaster) {
     // If the mechanism is not "default", then it does not need to be resolved
-    if (this.mechanism.match(/DEFAULT/i)) {
+    if (/DEFAULT/i.test(this.mechanism)) {
       return new MongoCredentials({
         username: this.username,
         password: this.password,
diff --git a/test/tools/runner/plugins/client_leak_checker.js b/test/tools/runner/plugins/client_leak_checker.js
index 7a74710978..f7999c44ac 100644
--- a/test/tools/runner/plugins/client_leak_checker.js
+++ b/test/tools/runner/plugins/client_leak_checker.js
@@ -30,7 +30,7 @@ function unifiedTopologyIsConnected(client) {
 }
 
 after(function() {
-  const isUnifiedTopology = this.configuration.usingUnifiedTopology;
+  const isUnifiedTopology = !!(this.configuration && this.configuration.usingUnifiedTopology);
   const traces = [];
   const openClientCount = activeClients.reduce((count, client) => {
     const isConnected = isUnifiedTopology