refactor(lsp,llm,hexailsp,appconfig): split long funcs; add tests

- Extract helpers to keep funcs <=50 lines; no behavior changes
- Add tests for prompt removal, code actions, and LLM request builders
- Table-drive TestInParamList; run gofmt

1 files changed, 63 insertions, 0 deletions

diff --git a/internal/lsp/codeaction_test.go b/internal/lsp/codeaction_test.go
new file mode 100644
index 0000000..e9abbb8
--- /dev/null
+++ b/internal/lsp/codeaction_test.go
@@ -0,0 +1,63 @@
+package lsp
+
+import (
+    "context"
+    "encoding/json"
+    "testing"
+    "hexai/internal/llm"
+)
+
+type fakeLLM struct{ resp string; err error }
+
+func (f fakeLLM) Chat(_ context.Context, _ []llm.Message, _ ...llm.RequestOption) (string, error) {
+    return f.resp, f.err
+}
+func (f fakeLLM) Name() string { return "fake" }
+func (f fakeLLM) DefaultModel() string { return "fake-model" }
+
+func TestBuildRewriteCodeAction_ReturnsEdit(t *testing.T) {
+    s := newTestServer()
+    s.llmClient = fakeLLM{resp: "REWRITTEN"}
+    p := CodeActionParams{TextDocument: TextDocumentIdentifier{URI: "file:///t.go"}, Range: Range{Start: Position{Line: 1, Character: 2}, End: Position{Line: 3, Character: 4}}}
+    sel := ";rewrite;\nold code"
+    ca := s.buildRewriteCodeAction(p, sel)
+    if ca == nil { t.Fatalf("expected code action") }
+    if ca.Edit == nil || len(ca.Edit.Changes) == 0 { t.Fatalf("expected workspace edit with changes") }
+    edits := ca.Edit.Changes[p.TextDocument.URI]
+    if len(edits) != 1 { t.Fatalf("expected 1 edit, got %d", len(edits)) }
+    if edits[0].Range != p.Range { t.Fatalf("edit range mismatch: got %+v want %+v", edits[0].Range, p.Range) }
+    if edits[0].NewText == "" { t.Fatalf("expected non-empty replacement text") }
+}
+
+func TestBuildRewriteCodeAction_NoInstruction(t *testing.T) {
+    s := newTestServer()
+    s.llmClient = fakeLLM{resp: "IGNORED"}
+    p := CodeActionParams{TextDocument: TextDocumentIdentifier{URI: "file:///t.go"}, Range: Range{}}
+    sel := "no instruction here"
+    if ca := s.buildRewriteCodeAction(p, sel); ca != nil { t.Fatalf("expected nil action when no instruction present") }
+}
+
+func TestBuildDiagnosticsCodeAction_ReturnsEdit(t *testing.T) {
+    s := newTestServer()
+    s.llmClient = fakeLLM{resp: "FIXED"}
+    p := CodeActionParams{TextDocument: TextDocumentIdentifier{URI: "file:///t.go"}, Range: Range{Start: Position{Line: 10}, End: Position{Line: 12, Character: 5}}}
+    ctx := CodeActionContext{Diagnostics: []Diagnostic{
+        {Range: Range{Start: Position{Line: 11}, End: Position{Line: 11, Character: 10}}, Message: "inside"},
+        {Range: Range{Start: Position{Line: 2}, End: Position{Line: 3}}, Message: "outside"},
+    }}
+    raw, _ := json.Marshal(ctx)
+    p.Context = json.RawMessage(raw)
+    sel := "some selected code"
+    ca := s.buildDiagnosticsCodeAction(p, sel)
+    if ca == nil { t.Fatalf("expected diagnostics code action") }
+    if ca.Edit == nil || len(ca.Edit.Changes) == 0 { t.Fatalf("expected workspace edit") }
+}
+
+func TestBuildDiagnosticsCodeAction_NoDiagnostics(t *testing.T) {
+    s := newTestServer()
+    s.llmClient = fakeLLM{resp: "FIXED"}
+    p := CodeActionParams{TextDocument: TextDocumentIdentifier{URI: "file:///t.go"}, Range: Range{}}
+    // empty context
+    p.Context = json.RawMessage(nil)
+    if ca := s.buildDiagnosticsCodeAction(p, "sel"); ca != nil { t.Fatalf("expected nil action when no diagnostics") }
+}