feat: Add a `disabled` configuration option for modules (#86)

• Add support for the disabled configuration option
This will allow you to selectively disable modules that you don't want or need. 😄
• Overwrite starship configuration file path with STARSHIP_CONFIG environment variable
• Write tests for the two configuration options that are available

24 files changed, 240 insertions, 104 deletions

diff --git a/Cargo.lock b/Cargo.lock
index ed8070901..943c7b47f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -818,6 +818,7 @@ dependencies = [
  "criterion 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "dirs 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "git2 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "pretty_env_logger 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/Cargo.toml b/Cargo.toml
index 641282208..097426fce 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,6 +15,7 @@ rayon = "1.1.0"
 pretty_env_logger = "0.3.0"
 log = "0.4.6"
 battery = "0.7.4"
+lazy_static = "1.3.0"
 
 [dev-dependencies]
 tempfile = "3.1.0"
diff --git a/src/config.rs b/src/config.rs
index 7c0509a2b..74ff447d2 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,4 +1,5 @@
 use crate::utils;
+use std::env;
 
 use dirs::home_dir;
 
@@ -20,9 +21,33 @@ impl Config {
 
     /// Create a config from a starship configuration file
     fn config_from_file() -> Option<toml::value::Table> {
-        let file_path = home_dir()?.join(".config/starship.toml");
-        let toml_content = utils::read_file(&file_path.to_str()?).ok()?;
-        log::trace!("Config file content: \n{}", &toml_content);
+        let file_path = match env::var("STARSHIP_CONFIG") {
+            Ok(path) => {
+                // Use $STARSHIP_CONFIG as the config path if available
+                log::debug!("STARSHIP_CONFIG is set: {}", &path);
+                path
+            }
+            Err(_) => {
+                // Default to using ~/.config/starhip.toml
+                log::debug!("STARSHIP_CONFIG is not set");
+                let config_path = home_dir()?.join(".config/starship.toml");
+                let config_path_str = config_path.to_str()?.to_owned();
+
+                log::debug!("Using default config path: {}", config_path_str);
+                config_path_str
+            }
+        };
+
+        let toml_content = match utils::read_file(&file_path) {
+            Ok(content) => {
+                log::trace!("Config file content: \n{}", &content);
+                Some(content)
+            }
+            Err(e) => {
+                log::debug!("Unable to read config file content: \n{}", &e);
+                None
+            }
+        }?;
 
         let config = toml::from_str(&toml_content).ok()?;
         log::debug!("Config found: \n{:?}", &config);
@@ -40,3 +65,35 @@ impl Config {
         module_config
     }
 }
+
+/// Extends `toml::value::Table` with useful methods
+pub trait TableExt {
+    fn get_as_bool(&self, key: &str) -> Option<bool>;
+}
+
+impl TableExt for toml::value::Table {
+    /// Get a key from a module's configuration as a boolean
+    fn get_as_bool(&self, key: &str) -> Option<bool> {
+        self.get(key).map(toml::Value::as_bool).unwrap_or(None)
+    }
+}
+
+mod tests {
+    use super::*;
+
+    #[test]
+    fn table_get_as_bool() {
+        let mut table = toml::value::Table::new();
+
+        // Use with boolean value
+        table.insert("boolean".to_string(), toml::value::Value::Boolean(true));
+        assert_eq!(table.get_as_bool("boolean"), Some(true));
+
+        // Use with string value
+        table.insert(
+            "string".to_string(),
+            toml::value::Value::String("true".to_string()),
+        );
+        assert_eq!(table.get_as_bool("string"), None);
+    }
+}
diff --git a/src/context.rs b/src/context.rs
index fd0ccc825..f62ea76cd 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -1,4 +1,4 @@
-use crate::config::Config;
+use crate::config::{Config, TableExt};
 use crate::module::Module;
 
 use clap::ArgMatches;
@@ -75,8 +75,23 @@ impl<'a> Context<'a> {
         dir
     }
 
-    pub fn new_module(&self, name: &str) -> Module {
-        Module::new(name, self.config.get_module_config(name))
+    /// Create a new module
+    ///
+    /// Will return `None` if the module is disabled by configuration, by setting
+    /// the `disabled` key to `true` in the configuration for that module.
+    pub fn new_module(&self, name: &str) -> Option<Module> {
+        let config = self.config.get_module_config(name);
+
+        // If the segment has "disabled" set to "true", don't show it
+        let disabled = config
+            .map(|table| table.get_as_bool("disabled"))
+            .unwrap_or(None);
+
+        if disabled == Some(true) {
+            return None;
+        }
+
+        Some(Module::new(name, config))
     }
 
     // returns a new ScanDir struct with reference to current dir_files of context
diff --git a/src/main.rs b/src/main.rs
index 70f68e2e5..371109e50 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -14,6 +14,20 @@ use clap::{App, Arg, SubCommand};
 fn main() {
     pretty_env_logger::init();
 
+    let status_code_arg = Arg::with_name("status_code")
+        .short("s")
+        .long("status")
+        .value_name("STATUS_CODE")
+        .help("The status code of the previously run command")
+        .takes_value(true);
+
+    let path_arg = Arg::with_name("path")
+        .short("p")
+        .long("path")
+        .value_name("PATH")
+        .help("The path that the prompt should render for")
+        .takes_value(true);
+
     let matches = App::new("Starship")
         .about("The cross-shell prompt for astronauts. ✨🚀")
         // pull the version number from Cargo.toml
@@ -24,22 +38,8 @@ fn main() {
         .subcommand(
             SubCommand::with_name("prompt")
                 .about("Prints the full starship prompt")
-                .arg(
-                    Arg::with_name("status_code")
-                        .short("s")
-                        .long("status")
-                        .value_name("STATUS_CODE")
-                        .help("The status code of the previously run command")
-                        .takes_value(true),
-                )
-                .arg(
-                    Arg::with_name("path")
-                        .short("p")
-                        .long("path")
-                        .value_name("PATH")
-                        .help("The path that the prompt should render for ($PWD by default)")
-                        .takes_value(true),
-                ),
+                .arg(&status_code_arg)
+                .arg(&path_arg),
         )
         .subcommand(
             SubCommand::with_name("module")
@@ -49,22 +49,8 @@ fn main() {
                         .help("The name of the module to be printed")
                         .required(true),
                 )
-                .arg(
-                    Arg::with_name("status_code")
-                        .short("s")
-                        .long("status")
-                        .value_name("STATUS_CODE")
-                        .help("The status code of the previously run command")
-                        .takes_value(true),
-                )
-                .arg(
-                    Arg::with_name("path")
-                        .short("p")
-                        .long("path")
-                        .value_name("PATH")
-                        .help("The path the prompt should render for ($PWD by default)")
-                        .takes_value(true),
-                ),
+                .arg(&status_code_arg)
+                .arg(&path_arg),
         )
         .get_matches();
 
diff --git a/src/modules/battery.rs b/src/modules/battery.rs
index 75ac1c554..048abe05f 100644
--- a/src/modules/battery.rs
+++ b/src/modules/battery.rs
@@ -3,7 +3,7 @@ use ansi_term::Color;
 use super::{Context, Module};
 
 /// Creates a segment for the battery percentage and charging state
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     const BATTERY_FULL: &str = "•";
     const BATTERY_CHARGING: &str = "⇡";
     const BATTERY_DISCHARGING: &str = "⇣";
@@ -22,7 +22,7 @@ pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
     }
 
     // TODO: Set style based on percentage when threshold is modifiable
-    let mut module = context.new_module("battery");
+    let mut module = context.new_module("battery")?;
     module.set_style(Color::Red.bold());
     module.get_prefix().set_value("");
 
@@ -61,7 +61,7 @@ fn get_battery_status() -> Option<BatteryStatus> {
             Some(battery_status)
         }
         Some(Err(e)) => {
-            log::debug!("Unable to access battery information:\n{}", e);
+            log::debug!("Unable to access battery information:\n{}", &e);
             None
         }
         None => {
diff --git a/src/modules/character.rs b/src/modules/character.rs
index 1a55cf78f..447fd759e 100644
--- a/src/modules/character.rs
+++ b/src/modules/character.rs
@@ -9,12 +9,12 @@ use ansi_term::Color;
 /// (green by default)
 /// - If the exit-code was anything else, the arrow will be formatted with
 /// `COLOR_FAILURE` (red by default)
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     const PROMPT_CHAR: &str = "➜";
     let color_success = Color::Green.bold();
     let color_failure = Color::Red.bold();
 
-    let mut module = context.new_module("char");
+    let mut module = context.new_module("char")?;
     module.get_prefix().set_value("");
 
     let symbol = module.new_segment("symbol", PROMPT_CHAR);
diff --git a/src/modules/directory.rs b/src/modules/directory.rs
index 8e719c452..a2cafac16 100644
--- a/src/modules/directory.rs
+++ b/src/modules/directory.rs
@@ -12,12 +12,12 @@ use super::{Context, Module};
 ///
 /// **Truncation**
 /// Paths will be limited in length to `3` path components by default.
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     const HOME_SYMBOL: &str = "~";
     const DIR_TRUNCATION_LENGTH: usize = 3;
     let module_color = Color::Cyan.bold();
 
-    let mut module = context.new_module("directory");
+    let mut module = context.new_module("directory")?;
     module.set_style(module_color);
 
     let current_dir = &context.current_dir;
diff --git a/src/modules/git_branch.rs b/src/modules/git_branch.rs
index 010c4eccb..d2861c47b 100644
--- a/src/modules/git_branch.rs
+++ b/src/modules/git_branch.rs
@@ -5,13 +5,13 @@ use super::{Context, Module};
 /// Creates a segment with the Git branch in the current directory
 ///
 /// Will display the branch name if the current directory is a git repo
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let branch_name = context.branch_name.as_ref()?;
 
     const GIT_BRANCH_CHAR: &str = " ";
     let segment_color = Color::Purple.bold();
 
-    let mut module = context.new_module("git_branch");
+    let mut module = context.new_module("git_branch")?;
     module.set_style(segment_color);
     module.get_prefix().set_value("on ");
 
diff --git a/src/modules/git_status.rs b/src/modules/git_status.rs
index 6db29ba12..c5ec57e4d 100644
--- a/src/modules/git_status.rs
+++ b/src/modules/git_status.rs
@@ -17,7 +17,7 @@ use super::{Context, Module};
 ///   - `+` — A new file has been added to the staging area
 ///   - `»` — A renamed file has been added to the staging area
 ///   - `✘` — A file's deletion has been added to the staging area
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     // This is the order that the sections will appear in
     const GIT_STATUS_CONFLICTED: &str = "=";
     const GIT_STATUS_AHEAD: &str = "⇡";
@@ -35,7 +35,7 @@ pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
     let repository = Repository::open(repo_root).ok()?;
 
     let module_style = Color::Red.bold();
-    let mut module = context.new_module("git_status");
+    let mut module = context.new_module("git_status")?;
     module.get_prefix().set_value("[").set_style(module_style);
     module.get_suffix().set_value("] ").set_style(module_style);
     module.set_style(module_style);
diff --git a/src/modules/go.rs b/src/modules/go.rs
index e4b689aff..a1b192e4a 100644
--- a/src/modules/go.rs
+++ b/src/modules/go.rs
@@ -13,7 +13,7 @@ use super::{Context, Module};
 ///     - Current directory contains a `Gopkg.lock` file
 ///     - Current directory contains a `.go` file
 ///     - Current directory contains a `Godeps` directory
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let is_go_project = context
         .new_scan_dir()
         .set_files(&["go.mod", "go.sum", "glide.yaml", "Gopkg.yml", "Gopkg.lock"])
@@ -30,7 +30,7 @@ pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
             const GO_CHAR: &str = "🐹 ";
             let module_color = Color::Cyan.bold();
 
-            let mut module = context.new_module("go");
+            let mut module = context.new_module("go")?;
             module.set_style(module_color);
 
             let formatted_version = format_go_version(go_version)?;
diff --git a/src/modules/line_break.rs b/src/modules/line_break.rs
index 0b11367ec..b86f85e38 100644
--- a/src/modules/line_break.rs
+++ b/src/modules/line_break.rs
@@ -1,10 +1,10 @@
 use super::{Context, Module};
 
 /// Creates a segment for the line break
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     const LINE_ENDING: &str = "\n";
 
-    let mut module = context.new_module("line_break");
+    let mut module = context.new_module("line_break")?;
 
     module.get_prefix().set_value("");
     module.get_suffix().set_value("");
diff --git a/src/modules/mod.rs b/src/modules/mod.rs
index cf1c64018..30a459ef1 100644
--- a/src/modules/mod.rs
+++ b/src/modules/mod.rs
@@ -16,18 +16,18 @@ use crate::module::Module;
 
 pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
     match module {
-        "dir" | "directory" => directory::segment(context),
-        "char" | "character" => character::segment(context),
-        "node" | "nodejs" => nodejs::segment(context),
-        "rust" | "rustlang" => rust::segment(context),
-        "python" => python::segment(context),
-        "go" | "golang" => go::segment(context),
-        "line_break" => line_break::segment(context),
-        "package" => package::segment(context),
-        "git_branch" => git_branch::segment(context),
-        "git_status" => git_status::segment(context),
-        "username" => username::segment(context),
-        "battery" => battery::segment(context),
+        "dir" | "directory" => directory::module(context),
+        "char" | "character" => character::module(context),
+        "node" | "nodejs" => nodejs::module(context),
+        "rust" | "rustlang" => rust::module(context),
+        "python" => python::module(context),
+        "go" | "golang" => go::module(context),
+        "line_break" => line_break::module(context),
+        "package" => package::module(context),
+        "git_branch" => git_branch::module(context),
+        "git_status" => git_status::module(context),
+        "username" => username::module(context),
+        "battery" => battery::module(context),
 
         _ => panic!("Unknown module: {}", module),
     }
diff --git a/src/modules/nodejs.rs b/src/modules/nodejs.rs
index e542acf1e..9aa5a4376 100644
--- a/src/modules/nodejs.rs
+++ b/src/modules/nodejs.rs
@@ -9,7 +9,7 @@ use super::{Context, Module};
 ///     - Current directory contains a `.js` file
 ///     - Current directory contains a `package.json` file
 ///     - Current directory contains a `node_modules` directory
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let is_js_project = context
         .new_scan_dir()
         .set_files(&["package.json"])
@@ -26,7 +26,7 @@ pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
             const NODE_CHAR: &str = "⬢ ";
             let module_color = Color::Green.bold();
 
-            let mut module = context.new_module("node");
+            let mut module = context.new_module("node")?;
             module.set_style(module_color);
 
             let formatted_version = node_version.trim();
diff --git a/src/modules/package.rs b/src/modules/package.rs
index a9af63891..527d5eaec 100644
--- a/src/modules/package.rs
+++ b/src/modules/package.rs
@@ -8,13 +8,13 @@ use toml;
 /// Creates a segment with the current package version
 ///
 /// Will display if a version is defined for your Node.js or Rust project (if one exists)
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     match get_package_version() {
         Some(package_version) => {
             const PACKAGE_CHAR: &str = "📦 ";
             let module_color = Color::Red.bold();
 
-            let mut module = context.new_module("package");
+            let mut module = context.new_module("package")?;
             module.set_style(module_color);
             module.get_prefix().set_value("is ");
 
@@ -75,19 +75,21 @@ mod tests {
 
     #[test]
     fn test_extract_cargo_version() {
-        let cargo_with_version = r#"
+        let cargo_with_version = toml::toml! {
             [package]
             name = "starship"
             version = "0.1.0"
-            "#;
+        }
+        .to_string();
 
         let expected_version = Some("v0.1.0".to_string());
         assert_eq!(extract_cargo_version(&cargo_with_version), expected_version);
 
-        let cargo_without_version = r#"
+        let cargo_without_version = toml::toml! {
             [package]
             name = "starship"
-            "#;
+        }
+        .to_string();
 
         let expected_version = None;
         assert_eq!(
diff --git a/src/modules/python.rs b/src/modules/python.rs
index 8b72e5187..a1a36cd3a 100644
--- a/src/modules/python.rs
+++ b/src/modules/python.rs
@@ -10,7 +10,7 @@ use super::{Context, Module};
 ///     - Current directory contains a `.python-version` file
 ///     - Current directory contains a `requirements.txt` file
 ///     - Current directory contains a `pyproject.toml` file
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let is_py_project = context
         .new_scan_dir()
         .set_files(&["requirements.txt", ".python-version", "pyproject.toml"])
@@ -26,7 +26,7 @@ pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
             const PYTHON_CHAR: &str = "🐍 ";
             let module_color = Color::Yellow.bold();
 
-            let mut module = context.new_module("python");
+            let mut module = context.new_module("python")?;
             module.set_style(module_color);
 
             let formatted_version = format_python_version(python_version);
diff --git a/src/modules/rust.rs b/src/modules/rust.rs
index 9ccdcc5d2..057344064 100644
--- a/src/modules/rust.rs
+++ b/src/modules/rust.rs
@@ -8,7 +8,7 @@ use super::{Context, Module};
 /// Will display the Rust version if any of the following criteria are met:
 ///     - Current directory contains a file with a `.rs` extension
 ///     - Current directory contains a `Cargo.toml` file
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let is_rs_project = context
         .new_scan_dir()
         .set_files(&["Cargo.toml"])
@@ -24,7 +24,7 @@ pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
             const RUST_CHAR: &str = "🦀 ";
             let module_color = Color::Red.bold();
 
-            let mut module = context.new_module("rust");
+            let mut module = context.new_module("rust")?;
             module.set_style(module_color);
 
             let formatted_version = format_rustc_version(rust_version);
@@ -38,14 +38,14 @@ pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
 }
 
 fn get_rust_version() -> Option<String> {
-    match Command::new("rustc").arg("-V").output() {
+    match Command::new("rustc").arg("--version").output() {
         Ok(output) => Some(String::from_utf8(output.stdout).unwrap()),
         Err(_) => None,
     }
 }
 
 fn format_rustc_version(mut rustc_stdout: String) -> String {
-    let offset = &rustc_stdout.find('(').unwrap();
+    let offset = &rustc_stdout.find('(').unwrap_or(rustc_stdout.len());
     let formatted_version: String = rustc_stdout.drain(..offset).collect();
 
     format!("v{}", formatted_version.replace("rustc", "").trim())
@@ -65,5 +65,8 @@ mod tests {
 
         let stable_input = String::from("rustc 1.34.0 (91856ed52 2019-04-10)");
         assert_eq!(format_rustc_version(stable_input), "v1.34.0");
+
+        let version_without_hash = String::from("rustc 1.34.0");
+        assert_eq!(format_rustc_version(version_without_hash), "v1.34.0");
     }
 }
diff --git a/src/modules/username.rs b/src/modules/username.rs
index 8885791b9..73295b79e 100644
--- a/src/modules/username.rs
+++ b/src/modules/username.rs
@@ -10,7 +10,7 @@ use super::{Context, Module};
 ///     - The current user isn't the same as the one that is logged in ($LOGNAME != $USER)
 ///     - The current user is root (UID = 0)
 ///     - The user is currently connected as an SSH session ($SSH_CONNECTION)
-pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let user = env::var("USER").ok();
     let logname = env::var("LOGNAME").ok();
     let ssh_connection = env::var("SSH_CONNECTION").ok();
@@ -18,7 +18,7 @@ pub fn segment<'a>(context: &'a Context) -> Option<Module<'a>> {
     let mut module_color = Color::Yellow.bold();
 
     if user != logname || ssh_connection.is_some() || is_root(&mut module_color) {
-        let mut module = context.new_module("username");
+        let mut module = context.new_module("username")?;
         module.set_style(module_color);
         module.new_segment("username", user?);
 
diff --git a/src/print.rs b/src/print.rs
index 71d453e34..ae712e123 100644
--- a/src/print.rs
+++ b/src/print.rs
@@ -6,21 +6,22 @@ use crate::context::Context;
 use crate::module::Module;
 use crate::modules;
 
+const PROMPT_ORDER: &[&str] = &[
+    "battery",
+    "username",
+    "directory",
+    "git_branch",
+    "git_status",
+    "package",
+    "nodejs",
+    "rust",
+    "python",
+    "go",
+    "line_break",
+    "character",
+];
+
 pub fn prompt(args: ArgMatches) {
-    let prompt_order = vec![
-        "battery",
-        "username",
-        "directory",
-        "git_branch",
-        "git_status",
-        "package",
-        "nodejs",
-        "rust",
-        "python",
-        "go",
-        "line_break",
-        "character",
-    ];
     let context = Context::new(args);
 
     let stdout = io::stdout();
@@ -29,7 +30,7 @@ pub fn prompt(args: ArgMatches) {
     // Write a new line before the prompt
     writeln!(handle).unwrap();
 
-    let modules = prompt_order
+    let modules = PROMPT_ORDER
         .par_iter()
         .map(|module| modules::handle(module, &context)) // Compute modules
         .flatten()
diff --git a/tests/fixtures/empty_config.toml b/tests/fixtures/empty_config.toml
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tests/fixtures/empty_config.toml
diff --git a/tests/testsuite/common.rs b/tests/testsuite/common.rs
index 451880288..ee817d8d5 100644
--- a/tests/testsuite/common.rs
+++ b/tests/testsuite/common.rs
@@ -1,15 +1,36 @@
+use lazy_static::lazy_static;
+use std::io::prelude::*;
+use std::path::{Path, PathBuf};
 use std::{io, process};
 
-pub fn render_prompt() -> process::Command {
+lazy_static! {
+    static ref MANIFEST_DIR: &'static Path = Path::new(env!("CARGO_MANIFEST_DIR"));
+    pub static ref FIXTURES_DIR: PathBuf = MANIFEST_DIR.join("tests/fixtures");
+    static ref EMPTY_CONFIG: PathBuf = MANIFEST_DIR.join("empty_config.toml");
+}
+
+/// Run an instance of starship
+fn run_starship() -> process::Command {
     let mut command = process::Command::new("./target/debug/starship");
-    command.arg("prompt");
+
+    command
+        .arg("prompt")
+        .env_clear()
+        .env("PATH", env!("PATH")) // Provide the $PATH variable so that external programs are runnable
+        .env("STARSHIP_CONFIG", EMPTY_CONFIG.as_os_str());
 
     command
 }
 
 pub fn render_module(module_name: &str) -> process::Command {
     let mut command = process::Command::new("./target/debug/starship");
-    command.arg("module").arg(module_name);
+
+    command
+        .arg("module")
+        .arg(module_name)
+        .env_clear()
+        .env("PATH", env!("PATH")) // Provide the $PATH variable so that external programs are runnable
+        .env("STARSHIP_CONFIG", EMPTY_CONFIG.as_os_str());
 
     command
 }
@@ -20,3 +41,21 @@ pub fn new_tempdir() -> io::Result<tempfile::TempDir> {
     // "/var/folders", which provides us with restricted permissions (rwxr-xr-x)
     tempfile::tempdir_in("/tmp")
 }
+
+/// Extends `std::process::Command` with methods for testing
+pub trait TestCommand {
+    fn use_config(&mut self, toml: toml::value::Value) -> &mut process::Command;
+}
+
+impl TestCommand for process::Command {
+    /// Create a configuration file with the provided TOML and use it
+    fn use_config(&mut self, toml: toml::value::Value) -> &mut process::Command {
+        // Create a persistent config file in a tempdir
+        let (mut config_file, config_path) =
+            tempfile::NamedTempFile::new().unwrap().keep().unwrap();
+        write!(config_file, "{}", toml.to_string()).unwrap();
+
+        // Set that newly-created file as the config for the prompt instance
+        self.env("STARSHIP_CONFIG", config_path)
+    }
+}
diff --git a/tests/testsuite/configuration.rs b/tests/testsuite/configuration.rs
new file mode 100644
index 000000000..231e0b99a
--- /dev/null
+++ b/tests/testsuite/configuration.rs
@@ -0,0 +1,34 @@
+use ansi_term::Color;
+use std::io;
+
+use crate::common::{self, TestCommand};
+
+#[test]
+fn char_symbol_configuration() -> io::Result<()> {
+    let expected = format!("{} ", Color::Green.bold().paint("❯"));
+
+    let output = common::render_module("char")
+        .use_config(toml::toml! {
+            [char]
+            symbol = "❯"
+        })
+        .output()?;
+    let actual = String::from_utf8(output.stdout).unwrap();
+    assert_eq!(expected, actual);
+
+    Ok(())
+}
+
+#[test]
+fn disabled_module() -> io::Result<()> {
+    let output = common::render_module("package")
+        .use_config(toml::toml! {
+            [package]
+            disabled = true
+        })
+        .output()?;
+    let actual = String::from_utf8(output.stdout).unwrap();
+    assert_eq!("", actual);
+
+    Ok(())
+}
diff --git a/tests/testsuite/main.rs b/tests/testsuite/main.rs
index 1705ae3ae..d7989e7ad 100644
--- a/tests/testsuite/main.rs
+++ b/tests/testsuite/main.rs
@@ -1,5 +1,6 @@
 mod character;
 mod common;
+mod configuration;
 mod directory;
 mod golang;
 mod line_break;
diff --git a/tests/testsuite/username.rs b/tests/testsuite/username.rs
index ed71e3239..49b1d6377 100644
--- a/