diff --git a/src/lib.rs b/src/lib.rs
index ccfa6b0..1be80d2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,6 +2,7 @@ use clap::{Parser, Subcommand};
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use std::fs;
+use std::process::Command;
 use std::path::Path;
 
 #[derive(Parser)]
@@ -15,7 +16,7 @@ pub struct Cli {
 
 #[derive(Subcommand)]
 pub enum Commands {
-    Install { name: Option<String>, version: Option<String>, requirements: Option<String> },
+    Install { packages: Vec<String> },
     Delete { name: String },
     Update { name: String, version: String },
     List,
@@ -62,8 +63,6 @@ pub fn run_command(_command: &str) -> bool {
 
 #[cfg(not(test))]
 pub fn run_command(command: &str) -> bool {
-    use std::process::Command;
-
     if cfg!(target_os = "windows") {
         Command::new("cmd")
             .args(&["/C", command])
@@ -80,18 +79,15 @@ pub fn run_command(command: &str) -> bool {
     }
 }
 
-pub fn install_package(name: &str, version: Option<&str>, packages: &mut PackageRegistry) {
-    let version = version.unwrap_or("latest");
-    let install_command = if version == "latest" {
-        format!("pip install {}", name)
-    } else {
-        format!("pip install {}=={}", name, version)
-    };
-    if run_command(&install_command) {
-        packages.packages.insert(name.to_string(), version.to_string());
-        println!("Package {} installed successfully", name);
-    } else {
-        println!("Failed to install package {}", name);
+pub fn install_packages(package_names: &[String], packages: &mut PackageRegistry) {
+    for name in package_names {
+        let install_command = format!("pip install {}", name);
+        if run_command(&install_command) {
+            packages.packages.insert(name.clone(), "latest".to_string());
+            println!("Package {} installed successfully", name);
+        } else {
+            println!("Failed to install package {}", name);
+        }
     }
 }
 
@@ -118,7 +114,13 @@ pub fn install_from_requirements(requirements: &str, packages: &mut PackageRegis
     if let Ok(data) = fs::read_to_string(requirements) {
         if let Ok(registry) = serde_json::from_str::<PackageRegistry>(&data) {
             for (name, version) in registry.packages {
-                install_package(&name, Some(&version), packages);
+                let install_command = format!("pip install {}=={}", name, version);
+                if run_command(&install_command) {
+                    packages.packages.insert(name.clone(), version.clone());
+                    println!("Package {} installed successfully", name);
+                } else {
+                    println!("Failed to install package {}", name);
+                }
             }
         } else {
             println!("Failed to parse the requirements file.");
diff --git a/src/main.rs b/src/main.rs
index e86385c..fd06482 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,30 +1,29 @@
 use clap::Parser;
-use python_package_manager::{Cli, Commands, load_packages, save_packages, install_package, delete_package, update_package, list_packages, install_from_requirements};
+use python_package_manager::{Cli, Commands, load_packages, save_packages, install_packages, delete_package, update_package, list_packages, install_from_requirements};
 
 fn main() {
     let args = Cli::parse();
-    let mut packages = load_packages();
+    let mut package_registry = load_packages();
 
     match args.command {
-        Commands::Install { name, version, requirements } => {
-            if let Some(requirements) = requirements {
-                install_from_requirements(&requirements, &mut packages);
-            } else if let Some(name) = name {
-                install_package(&name, version.as_deref(), &mut packages);
+        Commands::Install { packages } => {
+            if packages.len() == 1 && packages[0].starts_with("-r=") {
+                let requirements_path = &packages[0][3..];
+                install_from_requirements(requirements_path, &mut package_registry);
             } else {
-                println!("You must specify a package name or a requirements file.");
+                install_packages(&packages, &mut package_registry);
             }
         }
         Commands::Delete { name } => {
-            delete_package(&name, &mut packages);
+            delete_package(&name, &mut package_registry);
         }
         Commands::Update { name, version } => {
-            update_package(&name, &version, &mut packages);
+            update_package(&name, &version, &mut package_registry);
         }
         Commands::List => {
-            list_packages(&packages);
+            list_packages(&package_registry);
         }
     }
 
-    save_packages(&packages);
+    save_packages(&package_registry);
 }
diff --git a/tests/integration_tests.rs b/tests/integration_tests.rs
index d9efa0b..8b464af 100644
--- a/tests/integration_tests.rs
+++ b/tests/integration_tests.rs
@@ -1,6 +1,87 @@
 use std::fs;
+use std::path::Path;
+use std::process::{Command, Output};
 use tempfile::tempdir;
-use python_package_manager::{PackageRegistry, load_packages_from_path, save_packages_to_path, install_package, delete_package, update_package, list_packages};
+use python_package_manager::{PackageRegistry, load_packages_from_path, save_packages_to_path, install_packages, delete_package, update_package, list_packages, install_from_requirements};
+
+fn get_python_interpreter() -> String {
+    let version_output: Output = if cfg!(target_os = "windows") {
+        Command::new("cmd")
+            .args(&["/C", "where python"])
+            .output()
+            .expect("Failed to execute command")
+    } else {
+        Command::new("sh")
+            .arg("-c")
+            .arg("which python3")
+            .output()
+            .expect("Failed to execute command")
+    };
+
+    if !version_output.status.success() {
+        panic!("Failed to find Python interpreter: {}", String::from_utf8_lossy(&version_output.stderr));
+    }
+
+    let interpreter_path = String::from_utf8_lossy(&version_output.stdout)
+        .lines()
+        .next()
+        .expect("No Python interpreter found")
+        .to_string();
+
+    // Verify the Python version is 3.10 or above
+    let version_check = Command::new(&interpreter_path)
+        .arg("--version")
+        .output()
+        .expect("Failed to check Python version");
+
+    if !version_check.status.success() {
+        panic!("Failed to check Python version: {}", String::from_utf8_lossy(&version_check.stderr));
+    }
+
+    let version_str = String::from_utf8_lossy(&version_check.stdout);
+    if version_str.contains("Python 3.10") || version_str.contains("Python 3.11") {
+        interpreter_path
+    } else {
+        panic!("Python version 3.10 or above is required. Found: {}", version_str);
+    }
+}
+
+fn create_virtualenv(env_path: &Path) {
+    let python_interpreter = get_python_interpreter();
+
+    let output = Command::new(&python_interpreter)
+        .args(&["-m", "venv", env_path.to_str().unwrap()])
+        .output()
+        .expect("Failed to create virtual environment");
+
+    if !output.status.success() {
+        panic!(
+            "Failed to create virtual environment: {}",
+            String::from_utf8_lossy(&output.stderr)
+        );
+    }
+}
+
+fn run_command_in_virtualenv(env_path: &Path, args: &[&str]) -> bool {
+    let bin_path = if cfg!(target_os = "windows") {
+        env_path.join("Scripts").join("pip")
+    } else {
+        env_path.join("bin").join("pip")
+    };
+
+    let output = Command::new(bin_path)
+        .args(args)
+        .output()
+        .expect("Failed to run command in virtual environment");
+
+    if !output.status.success() {
+        println!("Command failed: {}", String::from_utf8_lossy(&output.stderr));
+    } else {
+        println!("Command succeeded: {}", String::from_utf8_lossy(&output.stdout));
+    }
+
+    output.status.success()
+}
 
 #[test]
 fn test_load_empty_packages() {
@@ -26,7 +107,7 @@ fn test_load_packages() {
 fn test_save_packages() {
     let dir = tempdir().expect("Failed to create temp dir");
     let file_path = dir.path().join("requirements.json");
-    let mut packages = PackageRegistry::new();
+    let mut packages: PackageRegistry = PackageRegistry::new();
     packages.packages.insert("pandas".to_string(), "1.0.0".to_string());
     save_packages_to_path(&packages, &file_path);
     let data = fs::read_to_string(&file_path).expect("Failed to read from temp file");
@@ -38,41 +119,71 @@ fn test_save_packages() {
 }
 
 #[test]
-fn test_install_package() {
+fn test_install_packages() {
     let dir = tempdir().expect("Failed to create temp dir");
-    let file_path: std::path::PathBuf = dir.path().join("requirements.json");
+    let env_path = dir.path().join("env");
+    create_virtualenv(&env_path);
+
+    let file_path = dir.path().join("requirements.json");
     fs::write(&file_path, "{}").expect("Failed to write to temp file");
+
     let mut packages = PackageRegistry::new();
-    install_package("pandas", Some("latest"), &mut packages);
+    let package_list = vec!["pandas".to_string(), "numpy".to_string(), "scipy".to_string()];
+    for package in &package_list {
+        if !run_command_in_virtualenv(&env_path, &["install", package]) {
+            panic!("Failed to install {}", package);
+        }
+    }
+
+    install_packages(&package_list, &mut packages);
     save_packages_to_path(&packages, &file_path);
     let updated_packages = load_packages_from_path(&file_path);
-    assert_eq!(updated_packages.packages.get("pandas").unwrap(), "latest");
+
+    for package in &package_list {
+        assert_eq!(updated_packages.packages.get(package).unwrap(), "latest");
+    }
 }
 
 #[test]
 fn test_delete_package() {
     let dir = tempdir().expect("Failed to create temp dir");
+    let env_path = dir.path().join("env");
+    create_virtualenv(&env_path);
+
     let file_path = dir.path().join("requirements.json");
     let mut packages = PackageRegistry::new();
     packages.packages.insert("pandas".to_string(), "1.0.0".to_string());
     save_packages_to_path(&packages, &file_path);
-    delete_package("pandas", &mut packages);
-    save_packages_to_path(&packages, &file_path);
-    let updated_packages = load_packages_from_path(&file_path);
-    assert!(updated_packages.packages.get("pandas").is_none());
+
+    if run_command_in_virtualenv(&env_path, &["uninstall", "-y", "pandas"]) {
+        delete_package("pandas", &mut packages);
+        save_packages_to_path(&packages, &file_path);
+        let updated_packages = load_packages_from_path(&file_path);
+        assert!(updated_packages.packages.get("pandas").is_none());
+    } else {
+        panic!("Failed to uninstall pandas");
+    }
 }
 
 #[test]
 fn test_update_package() {
     let dir = tempdir().expect("Failed to create temp dir");
+    let env_path = dir.path().join("env");
+    create_virtualenv(&env_path);
+
     let file_path = dir.path().join("requirements.json");
     let mut packages = PackageRegistry::new();
     packages.packages.insert("pandas".to_string(), "1.0.0".to_string());
     save_packages_to_path(&packages, &file_path);
-    update_package("pandas", "2.0.0", &mut packages);
-    save_packages_to_path(&packages, &file_path);
-    let updated_packages = load_packages_from_path(&file_path);
-    assert_eq!(updated_packages.packages.get("pandas").unwrap(), "2.0.0");
+
+    if run_command_in_virtualenv(&env_path, &["install", "pandas==2.0.0"]) {
+        update_package("pandas", "2.0.0", &mut packages);
+        save_packages_to_path(&packages, &file_path);
+        let updated_packages = load_packages_from_path(&file_path);
+        assert_eq!(updated_packages.packages.get("pandas").unwrap(), "2.0.0");
+    } else {
+        panic!("Failed to update pandas");
+    }
 }
 
 #[test]
@@ -84,3 +195,27 @@ fn test_list_packages() {
     save_packages_to_path(&packages, &file_path);
     list_packages(&packages); // This just prints to stdout, so we're testing for no panic
 }
+
+#[test]
+fn test_install_from_requirements() {
+    let dir = tempdir().expect("Failed to create temp dir");
+    let env_path = dir.path().join("env");
+    create_virtualenv(&env_path);
+
+    let file_path = dir.path().join("requirements.json");
+    let mut initial_packages = PackageRegistry::new();
+    initial_packages.packages.insert("pandas".to_string(), "1.0.0".to_string());
+    initial_packages.packages.insert("numpy".to_string(), "1.19.5".to_string());
+    save_packages_to_path(&initial_packages, &file_path);
+
+    println!("Content of requirements.json: {}", fs::read_to_string(&file_path).unwrap());
+
+    let mut packages = PackageRegistry::new();
+    install_from_requirements(file_path.to_str().unwrap(), &mut packages);
+
+    save_packages_to_path(&packages, &file_path);
+    let updated_packages = load_packages_from_path(&file_path);
+
+    assert_eq!(updated_packages.packages.get("pandas").unwrap(), "1.0.0");
+    assert_eq!(updated_packages.packages.get("numpy").unwrap(), "1.19.5");
+}