diff --git a/src/modules/aws.rs b/src/modules/aws.rs
index b404a2a27..870085b5d 100644
--- a/src/modules/aws.rs
+++ b/src/modules/aws.rs
@@ -126,7 +126,7 @@ mod tests {
     #[test]
     fn no_region_set() -> io::Result<()> {
         let actual = ModuleRenderer::new("aws").collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
@@ -384,7 +384,7 @@ region = us-east-2
                 format = "on [$symbol$region]($style) "
             })
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
diff --git a/src/modules/cmake.rs b/src/modules/cmake.rs
index ec078ce59..c8507c56a 100644
--- a/src/modules/cmake.rs
+++ b/src/modules/cmake.rs
@@ -67,7 +67,7 @@ mod tests {
     fn folder_without_cmake_lists() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
         let actual = ModuleRenderer::new("cmake").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/cmd_duration.rs b/src/modules/cmd_duration.rs
index 8684b0aa5..4abe29a6b 100644
--- a/src/modules/cmd_duration.rs
+++ b/src/modules/cmd_duration.rs
@@ -159,7 +159,7 @@ mod tests {
             .cmd_duration(1000)
             .collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         Ok(())
     }
@@ -185,7 +185,7 @@ mod tests {
             .cmd_duration(3000)
             .collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         Ok(())
     }
@@ -215,7 +215,7 @@ mod tests {
             .cmd_duration(1000)
             .collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         Ok(())
     }
diff --git a/src/modules/conda.rs b/src/modules/conda.rs
index 36762c4c3..552087846 100644
--- a/src/modules/conda.rs
+++ b/src/modules/conda.rs
@@ -63,7 +63,7 @@ mod tests {
     fn not_in_env() -> io::Result<()> {
         let actual = ModuleRenderer::new("conda").collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
@@ -79,7 +79,7 @@ mod tests {
             })
             .collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
diff --git a/src/modules/crystal.rs b/src/modules/crystal.rs
index 888cf83f7..b3d430eed 100644
--- a/src/modules/crystal.rs
+++ b/src/modules/crystal.rs
@@ -77,7 +77,7 @@ mod tests {
     fn folder_without_crystal_files() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
         let actual = ModuleRenderer::new("crystal").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
 
         dir.close()
diff --git a/src/modules/dart.rs b/src/modules/dart.rs
index a22690304..077159d18 100644
--- a/src/modules/dart.rs
+++ b/src/modules/dart.rs
@@ -83,7 +83,7 @@ mod tests {
     fn folder_without_dart_file() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
         let actual = ModuleRenderer::new("dart").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/dotnet.rs b/src/modules/dotnet.rs
index 0e0ad52b9..55c0acda7 100644
--- a/src/modules/dotnet.rs
+++ b/src/modules/dotnet.rs
@@ -366,7 +366,7 @@ mod tests {
     #[test]
     fn shows_nothing_in_directory_with_zero_relevant_files() -> io::Result<()> {
         let workspace = create_workspace(false)?;
-        expect_output(&workspace.path(), None)?;
+        expect_output(&workspace.path(), Some(String::from("")))?;
         workspace.close()
     }
 
diff --git a/src/modules/elixir.rs b/src/modules/elixir.rs
index 921e97afb..4785c65fd 100644
--- a/src/modules/elixir.rs
+++ b/src/modules/elixir.rs
@@ -96,7 +96,7 @@ Elixir 1.10 (compiled with Erlang/OTP 22)
     fn test_without_mix_file() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
 
-        let expected = None;
+        let expected = Some(String::from(""));
         let output = ModuleRenderer::new("elixir").path(dir.path()).collect();
 
         assert_eq!(output, expected);
diff --git a/src/modules/elm.rs b/src/modules/elm.rs
index a7da023be..f45c67d11 100644
--- a/src/modules/elm.rs
+++ b/src/modules/elm.rs
@@ -69,7 +69,7 @@ mod tests {
     fn folder_without_elm() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
         let actual = ModuleRenderer::new("elm").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/env_var.rs b/src/modules/env_var.rs
index 47af5074a..da990067d 100644
--- a/src/modules/env_var.rs
+++ b/src/modules/env_var.rs
@@ -65,7 +65,7 @@ mod test {
                 [env_var]
             })
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
@@ -94,7 +94,7 @@ mod test {
                 variable = "TEST_VAR"
             })
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
diff --git a/src/modules/erlang.rs b/src/modules/erlang.rs
index 8dc593c36..3d06d33b8 100644
--- a/src/modules/erlang.rs
+++ b/src/modules/erlang.rs
@@ -76,7 +76,7 @@ mod tests {
     fn test_without_config() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
 
-        let expected = None;
+        let expected = Some(String::from(""));
         let output = ModuleRenderer::new("erlang").path(dir.path()).collect();
 
         assert_eq!(output, expected);
diff --git a/src/modules/gcloud.rs b/src/modules/gcloud.rs
index 19064bb82..c733f6ad6 100644
--- a/src/modules/gcloud.rs
+++ b/src/modules/gcloud.rs
@@ -311,7 +311,7 @@ project = abc
                 format = "on [$symbol$region]($style) "
             })
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         dir.close()
diff --git a/src/modules/git_branch.rs b/src/modules/git_branch.rs
index bcebd83e6..44b73b4e5 100644
--- a/src/modules/git_branch.rs
+++ b/src/modules/git_branch.rs
@@ -87,7 +87,7 @@ mod tests {
         let actual = ModuleRenderer::new("git_branch")
             .path(repo_dir.path())
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         repo_dir.close()
diff --git a/src/modules/git_commit.rs b/src/modules/git_commit.rs
index ae80ee97b..28cb8ad7e 100644
--- a/src/modules/git_commit.rs
+++ b/src/modules/git_commit.rs
@@ -79,7 +79,7 @@ mod tests {
             .path(&repo_dir.path())
             .collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         repo_dir.close()
@@ -158,7 +158,7 @@ mod tests {
             .path(&repo_dir.path())
             .collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         repo_dir.close()
diff --git a/src/modules/git_state.rs b/src/modules/git_state.rs
index 40c9e9cda..4f112a07d 100644
--- a/src/modules/git_state.rs
+++ b/src/modules/git_state.rs
@@ -175,7 +175,7 @@ mod tests {
             .path(repo_dir.path())
             .collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         repo_dir.close()
diff --git a/src/modules/git_status.rs b/src/modules/git_status.rs
index 5e3ecb8ae..a4a33ccd3 100644
--- a/src/modules/git_status.rs
+++ b/src/modules/git_status.rs
@@ -408,7 +408,7 @@ mod tests {
         let actual = ModuleRenderer::new("git_status")
             .path(repo_dir.path())
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         repo_dir.close()
@@ -601,7 +601,7 @@ mod tests {
         let actual = ModuleRenderer::new("git_status")
             .path(&repo_dir.path())
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         repo_dir.close()
diff --git a/src/modules/golang.rs b/src/modules/golang.rs
index 80ff1b794..099b63fdd 100644
--- a/src/modules/golang.rs
+++ b/src/modules/golang.rs
@@ -97,7 +97,7 @@ mod tests {
 
         let actual = ModuleRenderer::new("golang").path(dir.path()).collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/helm.rs b/src/modules/helm.rs
index 06cd85da2..9755a0626 100644
--- a/src/modules/helm.rs
+++ b/src/modules/helm.rs
@@ -88,7 +88,7 @@ mod tests {
 
         let actual = ModuleRenderer::new("helm").path(dir.path()).collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/hg_branch.rs b/src/modules/hg_branch.rs
index 7b301945f..8ce203aec 100644
--- a/src/modules/hg_branch.rs
+++ b/src/modules/hg_branch.rs
@@ -120,7 +120,7 @@ mod tests {
             .path(repo_dir.path())
             .collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         repo_dir.close()
     }
@@ -279,7 +279,7 @@ mod tests {
         for expect in expectations {
             match expect {
                 Expect::Empty => {
-                    assert_eq!(None, actual);
+                    assert_eq!(Some(String::from("")), actual);
                     return Ok(());
                 }
                 Expect::Symbol(symbol) => {
diff --git a/src/modules/hostname.rs b/src/modules/hostname.rs
index c99482208..de7c15200 100644
--- a/src/modules/hostname.rs
+++ b/src/modules/hostname.rs
@@ -109,7 +109,7 @@ mod tests {
                 ssh_only = true
             })
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
diff --git a/src/modules/java.rs b/src/modules/java.rs
index e06182e3f..c4861f9f8 100644
--- a/src/modules/java.rs
+++ b/src/modules/java.rs
@@ -157,7 +157,7 @@ mod tests {
     fn folder_without_java_file() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
         let actual = ModuleRenderer::new("java").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/jobs.rs b/src/modules/jobs.rs
index 65a6ccc2e..10db5ea50 100644
--- a/src/modules/jobs.rs
+++ b/src/modules/jobs.rs
@@ -63,7 +63,7 @@ mod test {
     fn config_blank_job_0() -> io::Result<()> {
         let actual = ModuleRenderer::new("jobs").jobs(0).collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         Ok(())
     }
diff --git a/src/modules/julia.rs b/src/modules/julia.rs
index 11bfe7446..79383fff3 100644
--- a/src/modules/julia.rs
+++ b/src/modules/julia.rs
@@ -83,7 +83,7 @@ mod tests {
 
         let actual = ModuleRenderer::new("julia").path(dir.path()).collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/nim.rs b/src/modules/nim.rs
index 0b0d7ccad..396145406 100644
--- a/src/modules/nim.rs
+++ b/src/modules/nim.rs
@@ -101,7 +101,7 @@ mod tests {
         let dir = tempfile::tempdir()?;
         File::create(dir.path().join("nim.txt"))?.sync_all()?;
         let actual = ModuleRenderer::new("nim").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/nix_shell.rs b/src/modules/nix_shell.rs
index ab5fba084..a7433631c 100644
--- a/src/modules/nix_shell.rs
+++ b/src/modules/nix_shell.rs
@@ -69,7 +69,7 @@ mod tests {
     #[test]
     fn no_env_variables() -> io::Result<()> {
         let actual = ModuleRenderer::new("nix_shell").collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
@@ -80,7 +80,7 @@ mod tests {
         let actual = ModuleRenderer::new("nix_shell")
             .env("IN_NIX_SHELL", "something_wrong")
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
diff --git a/src/modules/nodejs.rs b/src/modules/nodejs.rs
index 1a3d087be..14146c170 100644
--- a/src/modules/nodejs.rs
+++ b/src/modules/nodejs.rs
@@ -70,7 +70,7 @@ mod tests {
     fn folder_without_node_files() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
         let actual = ModuleRenderer::new("nodejs").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
@@ -94,7 +94,7 @@ mod tests {
         fs::create_dir_all(&esy_lock)?;
 
         let actual = ModuleRenderer::new("nodejs").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/ocaml.rs b/src/modules/ocaml.rs
index 523f8bd55..8ed25491e 100644
--- a/src/modules/ocaml.rs
+++ b/src/modules/ocaml.rs
@@ -78,7 +78,7 @@ mod tests {
     fn folder_without_ocaml_file() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
         let actual = ModuleRenderer::new("ocaml").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/package.rs b/src/modules/package.rs
index 9b3dad294..49ce5aefb 100644
--- a/src/modules/package.rs
+++ b/src/modules/package.rs
@@ -759,7 +759,7 @@ end";
         if contains.is_some() {
             assert_eq!(actual, expected);
         } else {
-            assert_eq!(actual, None);
+            assert_eq!(actual, Some(String::from("")));
         }
 
         Ok(())
diff --git a/src/modules/perl.rs b/src/modules/perl.rs
index a3b33f1bf..5a09e17cf 100644
--- a/src/modules/perl.rs
+++ b/src/modules/perl.rs
@@ -75,7 +75,7 @@ mod tests {
 
         let actual = ModuleRenderer::new("perl").path(dir.path()).collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/php.rs b/src/modules/php.rs
index b85341c0b..e3f1d817e 100644
--- a/src/modules/php.rs
+++ b/src/modules/php.rs
@@ -89,7 +89,7 @@ mod tests {
 
         let actual = ModuleRenderer::new("php").path(dir.path()).collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/purescript.rs b/src/modules/purescript.rs
index 49dabc588..00e752213 100644
--- a/src/modules/purescript.rs
+++ b/src/modules/purescript.rs
@@ -64,7 +64,7 @@ mod tests {
     fn folder_without_purescript_files() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
         let actual = ModuleRenderer::new("purescript").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/python.rs b/src/modules/python.rs
index 8eb175ac0..9e24fd1f1 100644
--- a/src/modules/python.rs
+++ b/src/modules/python.rs
@@ -133,7 +133,7 @@ mod tests {
     fn folder_without_python_files() -> io::Result<()> {
         let dir = tempfile::tempdir()?;
         let actual = ModuleRenderer::new("python").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
 
         dir.close()
@@ -224,7 +224,7 @@ mod tests {
         let dir = tempfile::tempdir()?;
         File::create(dir.path().join("foo.py"))?.sync_all()?;
 
-        let expected = None;
+        let expected = Some(String::from(""));
         let config = toml::toml! {
             [python]
             scan_for_pyfiles = false
diff --git a/src/modules/ruby.rs b/src/modules/ruby.rs
index 477c4952f..3734f95f3 100644
--- a/src/modules/ruby.rs
+++ b/src/modules/ruby.rs
@@ -83,7 +83,7 @@ mod tests {
 
         let actual = ModuleRenderer::new("ruby").path(dir.path()).collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/shlvl.rs b/src/modules/shlvl.rs
index 2118c8010..e41cf6580 100644
--- a/src/modules/shlvl.rs
+++ b/src/modules/shlvl.rs
@@ -67,7 +67,7 @@ mod tests {
             })
             .env(SHLVL_ENV_VAR, "2")
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
@@ -96,7 +96,7 @@ mod tests {
                 disabled = false
             })
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
@@ -111,7 +111,7 @@ mod tests {
             })
             .env(SHLVL_ENV_VAR, "1")
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
@@ -143,7 +143,7 @@ mod tests {
             })
             .env(SHLVL_ENV_VAR, "1")
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
diff --git a/src/modules/singularity.rs b/src/modules/singularity.rs
index c408ddb2f..f4371f9ba 100644
--- a/src/modules/singularity.rs
+++ b/src/modules/singularity.rs
@@ -51,7 +51,7 @@ mod tests {
     fn no_env_set() -> io::Result<()> {
         let actual = ModuleRenderer::new("singularity").collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         Ok(())
     }
diff --git a/src/modules/swift.rs b/src/modules/swift.rs
index 32431179b..bab3d52a6 100644
--- a/src/modules/swift.rs
+++ b/src/modules/swift.rs
@@ -81,7 +81,7 @@ mod tests {
         let dir = tempfile::tempdir()?;
         File::create(dir.path().join("swift.txt"))?.sync_all()?;
         let actual = ModuleRenderer::new("swift").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }
diff --git a/src/modules/terraform.rs b/src/modules/terraform.rs
index e12aa3a9b..fc4e44486 100644
--- a/src/modules/terraform.rs
+++ b/src/modules/terraform.rs
@@ -194,7 +194,7 @@ is 0.12.14. You can update by downloading from www.terraform.io/downloads.html
         let dir = tempfile::tempdir()?;
 
         let actual = ModuleRenderer::new("terraform").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         dir.close()
diff --git a/src/modules/time.rs b/src/modules/time.rs
index f0228b68b..2a7bedd6b 100644
--- a/src/modules/time.rs
+++ b/src/modules/time.rs
@@ -485,7 +485,7 @@ mod tests {
     fn config_blank() -> io::Result<()> {
         let actual = ModuleRenderer::new("time").collect();
 
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         Ok(())
     }
diff --git a/src/modules/username.rs b/src/modules/username.rs
index ca05c3aee..784e86be7 100644
--- a/src/modules/username.rs
+++ b/src/modules/username.rs
@@ -75,7 +75,7 @@ mod tests {
     #[test]
     fn no_env_variables() -> io::Result<()> {
         let actual = ModuleRenderer::new("username").collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
@@ -87,7 +87,7 @@ mod tests {
             .env("LOGNAME", "astronaut")
             .env("USER", "astronaut")
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
@@ -99,7 +99,7 @@ mod tests {
         let actual = ModuleRenderer::new("username")
             .env("SSH_CONNECTION", "192.168.223.17 36673 192.168.223.229 22")
             .collect();
-        let expected = None;
+        let expected = Some(String::from(""));
 
         assert_eq!(expected, actual);
         Ok(())
diff --git a/src/modules/zig.rs b/src/modules/zig.rs
index b4f711f94..a4bbed37e 100644
--- a/src/modules/zig.rs
+++ b/src/modules/zig.rs
@@ -67,7 +67,7 @@ mod tests {
         let dir = tempfile::tempdir()?;
         File::create(dir.path().join("zig.txt"))?.sync_all()?;
         let actual = ModuleRenderer::new("zig").path(dir.path()).collect();
-        let expected = None;
+        let expected = Some(String::from(""));
         assert_eq!(expected, actual);
         dir.close()
     }