tex-fmt: add module

tex-fmt is a LaTeX source code formatter written in Rust, and uses
a user configuration file in the .toml format.

tests/modules/programs/tex-fmt/custom-settings.nix

@@ -0,0 +1,31 @@
+{ config, pkgs, ... }: {
+  config = {
+    programs.tex-fmt = {
+      enable = true;
+      settings = {
+        wrap = true;
+        tabsize = 2;
+        tabchar = "space";
+        lists = [ ];
+      };
+    };
+
+    nmt.script = let
+      expectedConfDir = if pkgs.stdenv.isDarwin then
+        "Library/Application Support"
+      else
+        ".config";
+      expectedConfigPath = "home-files/${expectedConfDir}/tex-fmt/tex-fmt.toml";
+    in ''
+      assertFileExists "${expectedConfigPath}"
+      assertFileContent "${expectedConfigPath}" ${
+        pkgs.writeText "tex-fmt.config-custom.expected" ''
+          lists = []
+          tabchar = "space"
+          tabsize = 2
+          wrap = true
+        ''
+      }
+    '';
+  };
+}

tests/modules/programs/tex-fmt/default-settings.nix

@@ -0,0 +1,15 @@
+{ config, pkgs, ... }: {
+  config = {
+    programs.tex-fmt = { enable = true; };
+
+    nmt.script = let
+      expectedConfDir = if pkgs.stdenv.isDarwin then
+        "Library/Application Support"
+      else
+        ".config";
+      expectedConfigPath = "home-files/${expectedConfDir}/tex-fmt/tex-fmt.toml";
+    in ''
+      assertPathNotExists "${expectedConfigPath}"
+    '';
+  };
+}

tests/modules/programs/tex-fmt/default.nix

@@ -0,0 +1,4 @@
+{
+  tex-fmt-default-settings = ./default-settings.nix;
+  tex-fmt-custom-settings = ./custom-settings.nix;
+}