Address PR #193 review: triggerKind comments, contextSupport, and tests

- Add inline comments (Invoked / TriggerCharacter) to triggerKind values
- Extract context-building into lsp_completion_context helper method
- Add contextSupport: true to textDocument.completion client capabilities
- Add test_client_capabilities assertion for completion contextSupport
- Add test/textbringer/commands/test_lsp.rb with 6 tests covering both
  branches of the trigger context selection logic

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: shugo

lib/textbringer/commands/lsp.rb

@@ -49,11 +49,7 @@ module Commands
         buffer.goto_char(start_point)
         buffer.point > 0 ? (buffer.backward_char; buffer.char_after) : nil
       }
-      context = if prefix.empty? && trigger_chars.include?(char_before_start)
-                  { triggerKind: 2, triggerCharacter: char_before_start }
-                else
-                  { triggerKind: 1 }
-                end
+      context = lsp_completion_context(prefix, trigger_chars, char_before_start)
 
       # Request completion
       client.completion(uri: uri, line: line, character: character, context: context) do |items, error|
@@ -186,6 +182,15 @@ module Commands
 
     # Helper methods
 
+    def lsp_completion_context(prefix, trigger_chars, char_before_start)
+      if prefix.empty? && trigger_chars.include?(char_before_start)
+        { triggerKind: 2, # TriggerCharacter
+          triggerCharacter: char_before_start }
+      else
+        { triggerKind: 1 } # Invoked
+      end
+    end
+
     # Convert a string's character length to UTF-16 code unit count.
     # LSP positions use UTF-16 offsets by default.
     def lsp_utf16_length(str)

lib/textbringer/lsp/client.rb

@@ -252,7 +252,8 @@ def client_capabilities
               },
               completionItemKind: {
                 valueSet: (1..25).to_a
-              }
+              },
+              contextSupport: true
             },
             signatureHelp: {
               signatureInformation: {

test/textbringer/commands/test_lsp.rb

@@ -0,0 +1,39 @@
+require_relative "../../test_helper"
+
+class TestLSPCommands < Textbringer::TestCase
+  def test_lsp_completion_context_invoked_with_prefix
+    # When there is a prefix typed, always use Invoked (triggerKind 1)
+    context = lsp_completion_context("fo", ["."], ".")
+    assert_equal({ triggerKind: 1 }, context)
+  end
+
+  def test_lsp_completion_context_invoked_no_trigger_char
+    # Empty prefix but char before start is not a trigger character
+    context = lsp_completion_context("", ["."], "x")
+    assert_equal({ triggerKind: 1 }, context)
+  end
+
+  def test_lsp_completion_context_invoked_no_trigger_chars_configured
+    # No trigger characters configured on the server
+    context = lsp_completion_context("", [], ".")
+    assert_equal({ triggerKind: 1 }, context)
+  end
+
+  def test_lsp_completion_context_trigger_character
+    # Empty prefix and char before start is a trigger character → TriggerCharacter (triggerKind 2)
+    context = lsp_completion_context("", ["."], ".")
+    assert_equal({ triggerKind: 2, triggerCharacter: "." }, context)
+  end
+
+  def test_lsp_completion_context_trigger_character_colon
+    # Empty prefix and :: trigger
+    context = lsp_completion_context("", [":", "::", "."], ":")
+    assert_equal({ triggerKind: 2, triggerCharacter: ":" }, context)
+  end
+
+  def test_lsp_completion_context_prefix_overrides_trigger_char
+    # Even when char before start is a trigger char, prefix present → Invoked
+    context = lsp_completion_context("bo", ["."], ".")
+    assert_equal({ triggerKind: 1 }, context)
+  end
+end

test/textbringer/lsp/test_client.rb

@@ -100,6 +100,7 @@ def test_client_capabilities
     assert(capabilities[:textDocument][:completion])
     assert(capabilities[:textDocument][:synchronization])
     refute(capabilities[:textDocument][:completion][:completionItem][:snippetSupport])
+    assert(capabilities[:textDocument][:completion][:contextSupport])
 
     # Signature help capabilities
     sig_help = capabilities[:textDocument][:signatureHelp]