diff --git a/.gitattributes b/.gitattributes
index 3dc7af676..2a808429e 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -9,6 +9,7 @@
 build/             export-ignore
 docs/              export-ignore
 examples/          export-ignore
+scripts/           export-ignore
 tests/             export-ignore
 .codecov.yml       export-ignore
 .editorconfig      export-ignore
diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index f1ac8782f..5b6aafacf 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -99,8 +99,8 @@ Code coverage is monitored for every PR and for the code base as a whole using [
 
 - [PHP][] >= 5.6
 - [Composer][]
-- [Python 3][]
-- [mitmproxy][] (`pip3 install mitmproxy`)
+- [Python 3][] >= 3.12
+- [mitmproxy][] >= 11.0.2 (`pip3 install mitmproxy`)
 
 [PHP]: https://www.php.net/
 [Composer]: http://getcomposer.org/
@@ -109,28 +109,65 @@ Code coverage is monitored for every PR and for the code base as a whole using [
 
 ### Running the Tests
 
+There are several ways to run the tests locally:
+
+#### 1. Using Composer Scripts (Recommended)
+
+The simplest way to run tests is using the Composer scripts:
+
+```bash
+# Run tests without coverage
+composer test
+
+# Run tests with coverage
+composer coverage
+
+# Run tests with automatic test server management
+composer test:withserver
+```
+
+#### 2. Manual Test Environment Management
+
+If you need more control over the test environment, you can manage it manually:
+
+```bash
+# Start all test servers and set environment variables
+# We need to source the script to properly set environment variables in our shell
+source scripts/start-test-environment.sh
+
+# Now run your tests
+composer test
+
+# When done, stop all servers
+./scripts/stop-test-environment.sh
+```
+
+Note: The environment scripts must be sourced (using `source` or `.`) to properly set environment variables in your shell.
+
+#### 3. Individual Component Control
+
+For debugging or development, you might want to manage individual components:
+
 ```bash
-# Start the test server
+# Start only the test server
 PORT=8080 vendor/bin/start.sh
-export "REQUESTS_TEST_HOST_HTTP=localhost:8080"
+export REQUESTS_TEST_HOST_HTTP=localhost:8080
 
-# Start the proxy server
+# Start only the proxy servers
 PORT=9002 tests/utils/proxy/start.sh
 PORT=9003 AUTH="test:pass" tests/utils/proxy/start.sh
-export "REQUESTS_HTTP_PROXY=localhost:9002"
-export "REQUESTS_HTTP_PROXY_AUTH=localhost:9003"
-export "REQUESTS_HTTP_PROXY_AUTH_USER=test"
-export "REQUESTS_HTTP_PROXY_AUTH_PASS=pass"
+export REQUESTS_HTTP_PROXY=localhost:9002
+export REQUESTS_HTTP_PROXY_AUTH=localhost:9003
+export REQUESTS_HTTP_PROXY_AUTH_USER=test
+export REQUESTS_HTTP_PROXY_AUTH_PASS=pass
+```
 
-# Run the tests
-composer test
+Remember to stop any servers you start:
 
-# Stop the proxy server
-PORT=9002 tests/utils/proxy/stop.sh
+```bash
+vendor/bin/stop.sh                   # Stop test server
+PORT=9002 tests/utils/proxy/stop.sh  # Stop proxy servers
 PORT=9003 tests/utils/proxy/stop.sh
-
-# Stop the test server
-vendor/bin/stop.sh
 ```
 
 To run the test with code coverage, use `composer coverage` instead.
diff --git a/.github/workflows/quicktest.yml b/.github/workflows/quicktest.yml
index fae653090..dbfdb4f7c 100644
--- a/.github/workflows/quicktest.yml
+++ b/.github/workflows/quicktest.yml
@@ -90,18 +90,9 @@ jobs:
       - name: Access localhost on port 9002
         run: curl -i http://localhost:9002
 
-      - name: Grab PHPUnit version
-        id: phpunit_version
-        run: echo "VERSION=$(vendor/bin/phpunit --version | grep --only-matching --max-count=1 --extended-regexp '\b[0-9]+\.[0-9]+')" >> "$GITHUB_OUTPUT"
-
-      - name: Run the unit tests (PHPUnit < 10)
-        if: ${{ ! startsWith( steps.phpunit_version.outputs.VERSION, '10.' ) }}
+      - name: Run the unit tests
         run: composer test
 
-      - name: Run the unit tests (PHPUnit 10+)
-        if: ${{ startsWith( steps.phpunit_version.outputs.VERSION, '10.' ) }}
-        run: composer test10
-
       - name: Stop proxy server
         continue-on-error: true
         run: |
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 4e04b5de2..7669ef610 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -114,26 +114,14 @@ jobs:
       - name: Access localhost on port 9002
         run: curl -i http://localhost:9002
 
-      - name: Grab PHPUnit version
-        id: phpunit_version
-        run: echo "VERSION=$(vendor/bin/phpunit --version | grep --only-matching --max-count=1 --extended-regexp '\b[0-9]+\.[0-9]+')" >> "$GITHUB_OUTPUT"
-
-      - name: Run the unit tests, no code coverage (PHPUnit < 10)
-        if: ${{  matrix.coverage == false && ! startsWith( steps.phpunit_version.outputs.VERSION, '10.' ) }}
+      - name: Run the unit tests, no code coverage
+        if: ${{ matrix.coverage == false }}
         run: composer test
 
-      - name: Run the unit tests, no code coverage (PHPUnit 10+)
-        if: ${{  matrix.coverage == false && startsWith( steps.phpunit_version.outputs.VERSION, '10.' ) }}
-        run: composer test10
-
-      - name: Run the unit tests with code coverage (PHPUnit < 10)
-        if: ${{  matrix.coverage == true && ! startsWith( steps.phpunit_version.outputs.VERSION, '10.' ) }}
+      - name: Run the unit tests with code coverage
+        if: ${{ matrix.coverage == true }}
         run: composer coverage -- --coverage-clover clover.xml
 
-      - name: Run the unit tests with code coverage (PHPUnit 10+)
-        if: ${{  matrix.coverage == true && startsWith( steps.phpunit_version.outputs.VERSION, '10.' ) }}
-        run: composer coverage10 -- --coverage-clover clover.xml
-
       - name: Stop proxy server
         continue-on-error: true
         run: |
diff --git a/.gitignore b/.gitignore
index 8f4479dd1..bb57d438f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,3 +27,4 @@ certificates/etag-*.txt
 # Ignore temporary files generated by the testing proxy.
 tests/utils/proxy/__pycache__
 tests/utils/proxy/*.pid
+tests/utils/pids
diff --git a/composer.json b/composer.json
index 98477ced9..f5aca4cbb 100644
--- a/composer.json
+++ b/composer.json
@@ -87,25 +87,45 @@
       "@php ./vendor/squizlabs/php_codesniffer/bin/phpcbf"
     ],
     "test": [
-      "@php ./vendor/phpunit/phpunit/phpunit --no-coverage"
-    ],
-    "test10": [
-      "@php ./vendor/phpunit/phpunit/phpunit -c phpunit10.xml.dist --no-coverage"
+      "./scripts/run-phpunit.sh --no-coverage"
     ],
     "coverage": [
-      "@php ./vendor/phpunit/phpunit/phpunit"
+      "./scripts/run-phpunit.sh"
+    ],
+    "testserver:start": [
+      "./scripts/start-test-environment.sh"
+    ],
+    "testserver:stop": [
+      "./scripts/stop-test-environment.sh"
+    ],
+    "test:withserver": [
+      "@putenv REQUESTS_HTTP_PROXY=localhost:9002",
+      "@putenv REQUESTS_HTTP_PROXY_AUTH=localhost:9003",
+      "@putenv REQUESTS_HTTP_PROXY_AUTH_USER=test",
+      "@putenv REQUESTS_HTTP_PROXY_AUTH_PASS=pass",
+      "@testserver:start",
+      "@test",
+      "@testserver:stop"
     ],
-    "coverage10": [
-      "@php ./vendor/phpunit/phpunit/phpunit -c phpunit10.xml.dist"
+    "coverage:withserver": [
+      "@putenv REQUESTS_HTTP_PROXY=localhost:9002",
+      "@putenv REQUESTS_HTTP_PROXY_AUTH=localhost:9003",
+      "@putenv REQUESTS_HTTP_PROXY_AUTH_USER=test",
+      "@putenv REQUESTS_HTTP_PROXY_AUTH_PASS=pass",
+      "@testserver:start",
+      "@coverage",
+      "@testserver:stop"
     ]
   },
   "scripts-descriptions": {
     "lint": "Lint PHP files to find parse errors.",
     "checkcs": "Check the entire codebase for code-style issues.",
     "fixcs": "Fix all auto-fixable code-style issues in the entire codebase.",
-    "test": "Run the unit tests on PHPUnit 5.x - 9.x without code coverage.",
-    "test10": "Run the unit tests on PHPUnit 10.x without code coverage.",
-    "coverage": "Run the unit tests on PHPUnit 5.x - 9.x with code coverage.",
-    "coverage10": "Run the unit tests on PHPUnit 10.x with code coverage."
+    "test": "Run the unit tests without code coverage (auto-detects PHPUnit version)",
+    "coverage": "Run the unit tests with code coverage (auto-detects PHPUnit version)",
+    "testserver:start": "Start the test environment including test server and proxy servers (Note: environment variables will only be available in a sourced shell)",
+    "testserver:stop": "Stop all running test environment servers",
+    "test:withserver": "Start test servers, run PHPUnit tests with appropriate config, then stop servers",
+    "coverage:withserver": "Start test servers, run PHPUnit tests with code coverage, then stop servers"
   }
 }
diff --git a/scripts/run-phpunit.sh b/scripts/run-phpunit.sh
new file mode 100755
index 000000000..e147fd4e8
--- /dev/null
+++ b/scripts/run-phpunit.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+
+
+# Set up PHPUnit command
+# We're using composer exec to ensure we use the version of PHP that Composer
+# is locked into, instead of the version of PHP that the system provides.
+PHPUNIT="composer exec phpunit --"
+
+# Detect PHPUnit version
+PHPUNIT_VERSION=$($PHPUNIT --version | grep -oE '[0-9]+\.[0-9]+' | head -n 1)
+
+# Determine config file based on version
+if printf '%s\n%s\n' "10.0" "$PHPUNIT_VERSION" | sort -V -C 2>/dev/null; then
+    CONFIG_FILE="phpunit10.xml.dist"
+else
+    CONFIG_FILE="phpunit.xml.dist"
+fi
+
+# Run the tests
+$PHPUNIT -c "$CONFIG_FILE" "$@"
diff --git a/scripts/start-test-environment.sh b/scripts/start-test-environment.sh
new file mode 100755
index 000000000..df0adad1d
--- /dev/null
+++ b/scripts/start-test-environment.sh
@@ -0,0 +1,125 @@
+#!/bin/sh
+
+# Try to determine script location
+if [ -n "${BASH_SOURCE:-}" ]; then
+    # Bash-specific path resolution
+    # Shellcheck complains about POSIX arrays being unreferenced, but this bit
+    # conditionally run on Bash only.
+    # shellcheck disable=SC3054
+    SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+    PROJECT_ROOT="$(dirname "$SCRIPT_DIR")"
+else
+    # POSIX fallback - assume we're in the repository root
+    PROJECT_ROOT="$(pwd)"
+    SCRIPT_DIR="$PROJECT_ROOT/scripts"
+fi
+
+# Detect if we're being sourced (POSIX-compatible way)
+sourced=0
+if [ -n "$ZSH_EVAL_CONTEXT" ]; then 
+    case $ZSH_EVAL_CONTEXT in *:file:*) sourced=1;; esac
+elif [ -n "$KSH_VERSION" ]; then
+    [ "$(cd $(dirname -- "$0") && pwd -P)/$(basename -- "$0")" != "$(cd $(dirname -- "${.sh.file}") && pwd -P)/$(basename -- "${.sh.file}")" ] && sourced=1
+elif [ -n "$BASH_VERSION" ]; then
+    (return 0 2>/dev/null) && sourced=1
+else
+    # POSIX fallback - check if we can modify our environment
+    # Try to modify a test variable
+    TEST_VAR="test"
+    if [ -z "${TEST_VAR:-}" ]; then
+        sourced=0
+    else
+        sourced=1
+    fi
+fi
+
+if [ $sourced -eq 0 ]; then
+    echo "Warning: This script should be sourced to set environment variables"
+    echo "Please either:"
+    echo "1. Source this script:  source scripts/start-test-environment.sh"
+    echo "2. Or manually set these environment variables:"
+    echo "   export REQUESTS_TEST_HOST_HTTP=localhost:8080"
+    echo "   export REQUESTS_HTTP_PROXY=localhost:9002"
+    echo "   export REQUESTS_HTTP_PROXY_AUTH=localhost:9003"
+    echo "   export REQUESTS_HTTP_PROXY_AUTH_USER=test"
+    echo "   export REQUESTS_HTTP_PROXY_AUTH_PASS=pass"
+    if [ -n "${BASH_VERSION:-}" ]; then
+        exit 1
+    fi
+fi
+
+PID_DIR="${PROJECT_ROOT}/tests/utils/pids"
+
+# Check if mitmproxy is installed
+if ! command -v mitmdump >/dev/null 2>&1; then
+    echo "Error: mitmproxy is not installed. Please install it with: pip3 install mitmproxy"
+    return 1 2>/dev/null || exit 1
+fi
+
+# Get mitmproxy version and compare with minimum required
+MITM_VERSION=$(mitmdump --version | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' | head -n1)
+MINIMUM_VERSION="11.0.2"
+
+# POSIX-compatible version comparison
+if ! printf '%s\n%s\n' "$MINIMUM_VERSION" "$MITM_VERSION" | sort -V -C 2>/dev/null; then
+    echo "Error: mitmproxy version $MITM_VERSION is too old"
+    echo "Please upgrade to version $MINIMUM_VERSION or newer with: pip3 install --upgrade mitmproxy"
+    return 1 2>/dev/null || exit 1
+fi
+
+echo "Found mitmproxy version $MITM_VERSION"
+
+# Create directory for PID files if it doesn't exist
+mkdir -p "$PID_DIR"
+
+# Start the test server
+echo "Starting test server..."
+PORT=8080 "${PROJECT_ROOT}/vendor/bin/start.sh"
+echo $! > "${PID_DIR}/test-server.pid"
+REQUESTS_TEST_HOST_HTTP="localhost:8080"
+export REQUESTS_TEST_HOST_HTTP
+
+# Start proxy servers
+echo "Starting proxy servers..."
+PORT=9002 "${PROJECT_ROOT}/tests/utils/proxy/start.sh"
+echo $! > "${PID_DIR}/proxy-server.pid"
+
+PORT=9003 AUTH="test:pass" "${PROJECT_ROOT}/tests/utils/proxy/start.sh"
+echo $! > "${PID_DIR}/proxy-auth-server.pid"
+
+# Set environment variables
+REQUESTS_HTTP_PROXY="localhost:9002"
+REQUESTS_HTTP_PROXY_AUTH="localhost:9003"
+REQUESTS_HTTP_PROXY_AUTH_USER="test"
+REQUESTS_HTTP_PROXY_AUTH_PASS="pass"
+
+export REQUESTS_HTTP_PROXY
+export REQUESTS_HTTP_PROXY_AUTH
+export REQUESTS_HTTP_PROXY_AUTH_USER
+export REQUESTS_HTTP_PROXY_AUTH_PASS
+
+# Wait for servers to be ready
+echo "Waiting for servers to be ready..."
+sleep 2
+
+# Test server connections
+echo "Testing server connections..."
+if ! curl -s -I http://localhost:8080 >/dev/null 2>&1; then
+    echo "Test server not responding"
+    return 1 2>/dev/null || exit 1
+fi
+
+if ! curl -s -I http://localhost:9002 >/dev/null 2>&1; then
+    echo "Proxy server not responding"
+    return 1 2>/dev/null || exit 1
+fi
+
+echo "Test environment is ready!"
+echo "Environment variables set:"
+echo "REQUESTS_TEST_HOST_HTTP=localhost:8080"
+echo "REQUESTS_HTTP_PROXY=localhost:9002"
+echo "REQUESTS_HTTP_PROXY_AUTH=localhost:9003"
+echo "REQUESTS_HTTP_PROXY_AUTH_USER=test"
+echo "REQUESTS_HTTP_PROXY_AUTH_PASS=pass"
+
+return 0 2>/dev/null || exit 0
diff --git a/scripts/stop-test-environment.sh b/scripts/stop-test-environment.sh
new file mode 100755
index 000000000..279ec1edb
--- /dev/null
+++ b/scripts/stop-test-environment.sh
@@ -0,0 +1,54 @@
+#!/bin/sh
+
+# Try to determine script location
+if [ -n "${BASH_SOURCE:-}" ]; then
+    # Bash-specific path resolution
+    # Shellcheck complains about POSIX arrays being unreferenced, but this bit
+    # conditionally run on Bash only.
+    # shellcheck disable=SC3054
+    SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+    PROJECT_ROOT="$(dirname "$SCRIPT_DIR")"
+else
+    # POSIX fallback - assume we're in the repository root
+    PROJECT_ROOT="$(pwd)"
+    SCRIPT_DIR="$PROJECT_ROOT/scripts"
+fi
+
+PID_DIR="${PROJECT_ROOT}/tests/utils/pids"
+
+# Function to safely kill a process
+kill_process() {
+    pid_file="$1"
+    if [ -f "$pid_file" ]; then
+        pid=$(cat "$pid_file")
+        if kill -0 "$pid" 2>/dev/null; then
+            echo "Stopping process $pid"
+            kill "$pid"
+            rm "$pid_file"
+        else
+            echo "Process $pid not running"
+            rm "$pid_file"
+        fi
+    fi
+}
+
+# Stop all servers
+echo "Stopping test environment..."
+
+# Stop test server
+kill_process "${PID_DIR}/test-server.pid"
+"${PROJECT_ROOT}/vendor/bin/stop.sh"
+
+# Stop proxy servers
+PORT=9002 "${PROJECT_ROOT}/tests/utils/proxy/stop.sh"
+kill_process "${PID_DIR}/proxy-server.pid"
+
+PORT=9003 "${PROJECT_ROOT}/tests/utils/proxy/stop.sh"
+kill_process "${PID_DIR}/proxy-auth-server.pid"
+
+# Clean up PID directory if empty
+rmdir "${PID_DIR}" 2>/dev/null || true
+
+echo "Test environment stopped"
+
+return 0 2>/dev/null || exit 0