diff --git a/modules/programs/zsh/plugins/default.nix b/modules/programs/zsh/plugins/default.nix
index 5da6461f2..06f5179b6 100644
--- a/modules/programs/zsh/plugins/default.nix
+++ b/modules/programs/zsh/plugins/default.nix
@@ -102,31 +102,43 @@ in
 
       initContent = lib.mkMerge [
         (lib.mkOrder 560 (
-          lib.concatStrings (
-            map (plugin: ''
-              path+="${pluginsDir}/${plugin.name}"
-              fpath+="${pluginsDir}/${plugin.name}"
-              ${
-                (lib.optionalString (plugin.completions != [ ]) ''
-                  fpath+=(${
-                    lib.concatMapStringsSep " " (
-                      completion: "\"${pluginsDir}/${plugin.name}/${completion}\""
-                    ) plugin.completions
-                  })
-                '')
-              }
-            '') cfg.plugins
-          )
+          let
+            pluginNames = map (plugin: plugin.name) cfg.plugins;
+            completionPaths = lib.flatten (
+              map (plugin: map (completion: "${plugin.name}/${completion}") plugin.completions) cfg.plugins
+            );
+          in
+          ''
+            # Add plugin directories to PATH and fpath
+            ${lib.hm.zsh.define "plugin_dirs" pluginNames}
+            for plugin_dir in "''${plugin_dirs[@]}"; do
+              path+="${pluginsDir}/$plugin_dir"
+              fpath+="${pluginsDir}/$plugin_dir"
+            done
+            unset plugin_dir plugin_dirs
+            ${lib.optionalString (completionPaths != [ ]) ''
+              # Add completion paths to fpath
+              ${lib.hm.zsh.define "completion_paths" completionPaths}
+              for completion_path in "''${completion_paths[@]}"; do
+                fpath+="${pluginsDir}/$completion_path"
+              done
+              unset completion_path completion_paths
+            ''}
+          ''
         ))
 
         (lib.mkOrder 900 (
-          lib.concatStrings (
-            map (plugin: ''
-              if [[ -f "${pluginsDir}/${plugin.name}/${plugin.file}" ]]; then
-                source "${pluginsDir}/${plugin.name}/${plugin.file}"
-              fi
-            '') cfg.plugins
-          )
+          let
+            pluginPaths = map (plugin: "${plugin.name}/${plugin.file}") cfg.plugins;
+          in
+          ''
+            # Source plugins
+            ${lib.hm.zsh.define "plugins" pluginPaths}
+            for plugin in "''${plugins[@]}"; do
+              [[ -f "${pluginsDir}/$plugin" ]] && source "${pluginsDir}/$plugin"
+            done
+            unset plugin plugins
+          ''
         ))
       ];
     };
diff --git a/tests/modules/programs/zsh/history-substring-search-expected.zshrc b/tests/modules/programs/zsh/history-substring-search-expected.zshrc
new file mode 100644
index 000000000..a73c04322
--- /dev/null
+++ b/tests/modules/programs/zsh/history-substring-search-expected.zshrc
@@ -0,0 +1,57 @@
+typeset -U path cdpath fpath manpath
+for profile in ${(z)NIX_PROFILES}; do
+  fpath+=($profile/share/zsh/site-functions $profile/share/zsh/$ZSH_VERSION/functions $profile/share/zsh/vendor-completions)
+done
+
+HELPDIR="@zsh@/share/zsh/$ZSH_VERSION/help"
+
+autoload -U compinit && compinit
+# History options should be set in .zshrc and after oh-my-zsh sourcing.
+# See https://github.com/nix-community/home-manager/issues/177.
+HISTSIZE="10000"
+SAVEHIST="10000"
+
+HISTFILE="/home/hm-user/.zsh_history"
+mkdir -p "$(dirname "$HISTFILE")"
+
+setopt HIST_FCNTL_LOCK
+
+# Enabled history options
+enabled_opts=(
+  HIST_IGNORE_DUPS HIST_IGNORE_SPACE SHARE_HISTORY
+)
+for opt in "${enabled_opts[@]}"; do
+  setopt "$opt"
+done
+unset opt enabled_opts
+
+# Disabled history options
+disabled_opts=(
+  APPEND_HISTORY EXTENDED_HISTORY HIST_EXPIRE_DUPS_FIRST HIST_FIND_NO_DUPS
+  HIST_IGNORE_ALL_DUPS HIST_SAVE_NO_DUPS
+)
+for opt in "${disabled_opts[@]}"; do
+  unsetopt "$opt"
+done
+unset opt disabled_opts
+
+source @zsh-history-substring-search@/share/zsh-history-substring-search/zsh-history-substring-search.zsh
+
+# Bind search up keys
+search_up_keys=(
+  '^[[A' '\eOA'
+)
+ for key in "${search_up_keys[@]}"; do
+   bindkey "$key" history-substring-search-up
+ done
+ unset key search_up_keys
+
+# Bind search down keys
+search_down_keys=(
+  '^[[B'
+)
+ for key in "${search_down_keys[@]}"; do
+   bindkey "$key" history-substring-search-down
+ done
+ unset key search_down_keys
+
diff --git a/tests/modules/programs/zsh/history-substring-search.nix b/tests/modules/programs/zsh/history-substring-search.nix
index 5fe204c61..9232bc9c4 100644
--- a/tests/modules/programs/zsh/history-substring-search.nix
+++ b/tests/modules/programs/zsh/history-substring-search.nix
@@ -11,10 +11,8 @@
     };
   };
 
-  # Written with regex to ensure we don't end up missing newlines in the future
   nmt.script = ''
-    assertFileRegex home-files/.zshrc "^bindkey \"\^\[\[B\" history-substring-search-down$"
-    assertFileRegex home-files/.zshrc "^bindkey \"\^\[\[A\" history-substring-search-up$"
-    assertFileRegex home-files/.zshrc "^bindkey \"\\\\eOA\" history-substring-search-up$"
+    assertFileExists home-files/.zshrc
+    assertFileContent $(normalizeStorePaths home-files/.zshrc) ${./history-substring-search-expected.zshrc}
   '';
 }
diff --git a/tests/modules/programs/zsh/plugins.nix b/tests/modules/programs/zsh/plugins.nix
index 4756be3ef..d69b8095f 100644
--- a/tests/modules/programs/zsh/plugins.nix
+++ b/tests/modules/programs/zsh/plugins.nix
@@ -23,9 +23,29 @@ in
     test.stubs.zsh = { };
 
     nmt.script = ''
-      assertFileRegex home-files/.zshrc '^path+="/home/hm-user/.zsh/plugins/mockPlugin"$'
-      assertFileRegex home-files/.zshrc '^fpath+="/home/hm-user/.zsh/plugins/mockPlugin"$'
-      assertFileRegex home-files/.zshrc '^fpath+=("/home/hm-user/.zsh/plugins/mockPlugin/share/zsh/site-functions" "/home/hm-user/.zsh/plugins/mockPlugin/share/zsh/vendor-completions")$'
+      # Test the plugin directories loop structure
+      assertFileContains home-files/.zshrc '# Add plugin directories to PATH and fpath'
+      assertFileContains home-files/.zshrc 'plugin_dirs=('
+      assertFileContains home-files/.zshrc 'mockPlugin'
+      assertFileContains home-files/.zshrc 'for plugin_dir in "''${plugin_dirs[@]}"; do'
+      assertFileContains home-files/.zshrc 'path+="/home/hm-user/.zsh/plugins/$plugin_dir"'
+      assertFileContains home-files/.zshrc 'fpath+="/home/hm-user/.zsh/plugins/$plugin_dir"'
+
+      # Test the completion paths loop structure
+      assertFileContains home-files/.zshrc '# Add completion paths to fpath'
+      assertFileContains home-files/.zshrc 'completion_paths=('
+      assertFileContains home-files/.zshrc 'mockPlugin/share/zsh/site-functions'
+      assertFileContains home-files/.zshrc 'mockPlugin/share/zsh/vendor-completions'
+      assertFileContains home-files/.zshrc 'for completion_path in "''${completion_paths[@]}"; do'
+      assertFileContains home-files/.zshrc 'fpath+="/home/hm-user/.zsh/plugins/$completion_path"'
+
+      # Test the plugin loading structure
+      assertFileContains home-files/.zshrc '# Source plugins'
+      assertFileContains home-files/.zshrc 'plugins=('
+      assertFileContains home-files/.zshrc 'mockPlugin/share/mockPlugin/mockPlugin.plugin.zsh'
+      assertFileContains home-files/.zshrc 'for plugin in "''${plugins[@]}"; do'
+      assertFileContains home-files/.zshrc '[[ -f "/home/hm-user/.zsh/plugins/$plugin" ]] && source "/home/hm-user/.zsh/plugins/$plugin"'
+      assertFileContains home-files/.zshrc 'done'
     '';
   };
 }