workspaces: choose a reasonable default library name

Choose a default library to build, test, or use as the project for lsp-dylan if
no default is specified in workspace.json.

sources/workspaces/registry.dylan

@@ -8,7 +8,6 @@ end;
 //// REGISTRY
 
 // Keys used to lookup values in a parsed LID file.
-// TODO: use 'define enum' in uncommon-dylan
 define constant $platforms-key = #"platforms";
 define constant $files-key = #"files";
 define constant $library-key = #"library";
@@ -425,14 +424,23 @@ define function parse-lid-file
   lid
 end function;
 
-define function find-library-names
+
+// Find the names of all libraries defined in `dir`, a directory or registry.
+define generic find-library-names (dir) => (names :: <seq>);
+
+define method find-library-names
     (dir :: <directory-locator>) => (names :: <seq>)
-  let registry = make(<registry>, root-directory: dir);
+  find-library-names(make(<registry>, root-directory: dir))
+end method;
+
+define method find-library-names
+    (registry :: <registry>) => (names :: <seq>)
   // It's possible for a LID included via the LID: keyword to not have a library.
   remove(map(rcurry(lid-value, $library-key),
-             find-lids(registry, dir)),
+             find-lids(registry, registry.root-directory)),
          #f)
-end function;
+end method;
+
 
 // Build a map from source file names (absolute pathname strings) to the names
 // of libraries they belong to (a sequence of strings). For now we only look at

sources/workspaces/workspaces.dylan

@@ -142,10 +142,19 @@ define function load-workspace
   let ws-json = ws-file & load-json-file(ws-file);
   let default-library
     = ws-json & element(ws-json, $default-library-key, default: #f);
-  if (~default-library & active-packages.size = 1)
-    // TODO: this isn't right. Should find the actual libraries, from the LID
-    // files, and if there's only one "*-test*" library, choose that.
-    default-library := pm/package-name(active-packages[0]);
+  if (~default-library)
+    let libs = find-library-names(registry);
+    if (~empty?(libs))
+      local method match (suffix, lib)
+              ends-with?(lib, suffix) & lib
+            end;
+      // The assumption here is that (for small projects) there's usually one
+      // test library that you want to run.
+      default-library := (any?(curry(match, "-test-suite-app"), libs)
+                            | any?(curry(match, "-test-suite"), libs)
+                            | any?(curry(match, "-tests"), libs)
+                            | libs[0]);
+    end;
   end;
   make(<workspace>,
        active-packages: active-packages,