Add some unit tests for the {cwd} module.

To run them:

set CLINK_PATH=c:\repos\flexprompt;c:\repos\flexprompt\tests

The tests will automatically run.  Yes, it's cheesy.  But it's very
lightweight and simple for me to use.  Using a more sophisticated test
system would not be cost effective for me at this time.

flexprompt_modules.lua

@@ -1371,3 +1371,5 @@ end
 if rl.ismodifiedline then
 flexprompt.add_module( "modmark",   render_modmark                      )
 end
+
+_flexprompt_test_process_cwd_string = process_cwd_string

tests/cwd.lua

@@ -0,0 +1,75 @@
+local uht = flexprompt.settings.use_home_tilde
+
+local test_cwd          = "c:\\Users\\chrisant\\source\\repos\\win32-darkmode\\win32-darkmode\\x64"
+local test_git_dir      = "c:\\Users\\chrisant\\source\\repos\\win32-darkmode\\.git"
+
+local full              = "\x01c:\\Users\\chrisant\\source\\repos\\\x02win32-darkmode\\win32-darkmode\\x64"
+local short_all         = "\x01c:\\U\\c\\s\\r\\\x02w\\w\\x64"
+local short_rootsmart   = "\x01c:\\U\\c\\s\\r\\\x02win32-darkmode\\win32-darkmode\\x64"
+
+local tests =
+{
+    -- git    colors
+    { false,  false,    "cwd",                          full },
+    { false,  false,    "cwd:t=full:",                  full },
+    { false,  false,    "cwd:t=smart:",                 full },
+    { false,  false,    "cwd:s:",                       short_all },
+    { false,  false,    "cwd:s=rootsmart:",             short_all },
+    { false,  false,    "cwd:s:t=full:",                short_all },
+    { false,  false,    "cwd:s=rootsmart:t=full:",      short_all },
+    { false,  false,    "cwd:t=folder:",                "x64" },
+    { false,  false,    "cwd:s:t=folder:",              "x64" },
+    -- git
+    { true,   true,     "cwd",                          full },
+    { true,   false,    "cwd:t=full:",                  full },
+    { true,   false,    "cwd:t=smart:",                 "win32-darkmode\\win32-darkmode\\x64" },
+    { true,   true,     "cwd:s:",                       short_all },
+    { true,   true,     "cwd:s=rootsmart:",             short_rootsmart },
+    { true,   false,    "cwd:s:t=full:",                short_all },
+    { true,   false,    "cwd:s=rootsmart:t=full:",      short_all },
+    { true,   false,    "cwd:t=folder:",                "x64" },
+    { true,   false,    "cwd:s:t=folder:",              "x64" },
+}
+
+print("-- CWD MODULE TESTS ----------------------------------------------------")
+
+local i = 0
+for _,e in ipairs(tests) do
+    i = i + 1
+    for t = 1,2 do
+        flexprompt.settings.use_home_tilde = (t > 1)
+
+        local cwd = test_cwd
+        local git_dir = e[1] and test_git_dir or false
+
+        local r = _flexprompt_test_process_cwd_string(cwd, git_dir, e[3])
+        local num = tostring(i)
+        local name = e[3]
+
+        local x = e[4]
+        if not e[2] then
+            x = x:gsub("\x01", ""):gsub("\x02", "")
+        end
+        if (t > 1) then
+            x = x:gsub("c:\\Users\\chrisant", "~"):gsub("c:\\U\\c", "~")
+            num = num.."~"
+        end
+
+        if r == x then
+            clink.print(num, "\x1b[32mok\x1b[m", name)
+        else
+            clink.print(num, "\x1b[31mFAIL\x1b[m", name)
+            clink.print("", "", "\x1b[36mexpected:\x1b[m    "..x)
+            clink.print("", "", "\x1b[33m  actual:\x1b[m    "..r)
+        end
+    end
+end
+
+print("------------------------------------------------------------------------")
+
+flexprompt.settings.use_home_tilde = uht
+
+print()
+print()
+print()
+