tests: add more table-driven cases and negative provider tests; update report

4 files changed, 70 insertions, 2 deletions

diff --git a/REPORT.md b/REPORT.md
index 7da6b27..9c2dfa3 100644
--- a/REPORT.md
+++ b/REPORT.md
@@ -77,7 +77,7 @@ Legend: [ ] pending · [~] in progress · [x] done/partially done
 - [x] Expand Copilot mocked responses: multi-choice, error object in body; assert parsing and error propagation.
 
 6) General
-- [x] Convert repetitive tests to table-driven style where appropriate (e.g., completion prefix/strip; instruction markers; label/filter; code fences/inline spans).
+- [x] Convert repetitive tests to table-driven style where appropriate (e.g., completion prefix/strip; instruction markers; label/filter; code fences/inline spans; buildPrompts variants; computeTextEditAndFilter variants).
 - [ ] Introduce a shared set of realistic mock responses (multi-line code, markdown, malformed json) and reuse across tests.
 
 ## Progress (latest)
@@ -103,7 +103,7 @@ Legend: [ ] pending · [~] in progress · [x] done/partially done
 - [x] 3) lsp e2e chat/document: chat test now uses multi-line reply and validates insertion contains both lines; document resolve uses multi-line docblock.
 - [x] 4) lsp completion: manual-invoke test now uses a multi-line realistic function signature with body; still passes and exercises formatting.
 - [x] 5) llm providers: added OpenAI success + SSE stream and Copilot token+chat + Codex SSE tests; coverage ≥80%. Expanded with multi-choice and error-body cases.
-- [x] 6) General: introduced shared fixtures (internal/testutil) and added table-driven tests for code fences, inline spans, label selection, prefix stripping, and instruction markers. Documented patterns in docs/testing.md.
+- [x] 6) General: introduced shared fixtures (internal/testutil) and added table-driven tests for code fences, inline spans, label selection, prefix stripping, instruction markers, buildPrompts, and computeTextEditAndFilter. Documented patterns in docs/testing.md.
 - [x]    Added table-driven tests for instruction marker extraction and prefix stripping.
 
 ## Next actions (prioritized)
diff --git a/internal/llm/copilot_http_test.go b/internal/llm/copilot_http_test.go
index 30144d1..2e46d68 100644
--- a/internal/llm/copilot_http_test.go
+++ b/internal/llm/copilot_http_test.go
@@ -108,6 +108,25 @@ func TestCopilot_Chat_MultiChoice_And_ErrorBody(t *testing.T) {
     }
 }
 
+func TestCopilot_Chat_DecodeError_StatusOK(t *testing.T) {
+    // Chat returns 200 but invalid JSON; expect decode error
+    srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+        io.WriteString(w, "{invalid")
+    }))
+    defer srv.Close()
+    c := newCopilot(srv.URL, "gpt-4o-mini", "KEY", f64p(0.1)).(copilotClient)
+    tr := rtFunc2(func(r *http.Request) (*http.Response, error) {
+        if r.URL.Host == "api.github.com" && r.URL.Path == "/copilot_internal/v2/token" {
+            rw := httptest.NewRecorder(); _ = json.NewEncoder(rw).Encode(map[string]string{"token":"tok"}); res := rw.Result(); res.StatusCode = 200; return res, nil
+        }
+        return http.DefaultTransport.RoundTrip(r)
+    })
+    c.httpClient = &http.Client{Transport: tr, Timeout: 5 * time.Second}
+    if _, err := c.Chat(context.Background(), []Message{{Role:"user", Content:"hi"}}); err == nil {
+        t.Fatalf("expected decode error for invalid body")
+    }
+}
+
 func TestCopilot_CodeCompletion_MalformedAndEmpty(t *testing.T) {
     c := newCopilot("https://api.githubcopilot.com", "gpt-4o-mini", "API", f64p(0.1)).(copilotClient)
     tr := rtFunc2(func(r *http.Request) (*http.Response, error) {
diff --git a/internal/lsp/build_prompts_table_test.go b/internal/lsp/build_prompts_table_test.go
new file mode 100644
index 0000000..b0092e2
--- /dev/null
+++ b/internal/lsp/build_prompts_table_test.go
@@ -0,0 +1,16 @@
+package lsp
+
+import "testing"
+
+func TestBuildPrompts_Table(t *testing.T) {
+    p := CompletionParams{TextDocument: TextDocumentIdentifier{URI: "file:///x.go"}, Position: Position{Line:5, Character:7}}
+    cases := []struct{ name string; inParams bool }{
+        {"generic", false},
+        {"in_params", true},
+    }
+    for _, c := range cases {
+        sys, user := buildPrompts(c.inParams, p, "above", "current", "below", "func ctx")
+        if sys == "" || user == "" { t.Fatalf("%s: prompts empty", c.name) }
+    }
+}
+
diff --git a/internal/lsp/compute_textedit_table_test.go b/internal/lsp/compute_textedit_table_test.go
new file mode 100644
index 0000000..d82e91d
--- /dev/null
+++ b/internal/lsp/compute_textedit_table_test.go
@@ -0,0 +1,33 @@
+package lsp
+
+import "testing"
+
+func TestComputeTextEditAndFilter_Table(t *testing.T) {
+    cases := []struct{
+        name     string
+        inParams bool
+        current  string
+        pos      Position
+        cleaned  string
+    }{
+        {"ident_replace", false, "ab cd", Position{Line:1, Character:4}, "X"},
+        {"params_inside", true, "func add(a int, b string)", Position{Line:0, Character:15}, "c bool"},
+        {"params_at_close", true, "func add(a int)", Position{Line:0, Character:len("func add(a int)")}, "b string"},
+    }
+    for _, c := range cases {
+        te, filter := computeTextEditAndFilter(c.cleaned, c.inParams, c.current, CompletionParams{Position: c.pos})
+        if te == nil {
+            t.Fatalf("%s: expected edit", c.name)
+        }
+        if c.inParams && te.Range.Start.Character == 0 {
+            t.Fatalf("%s: expected param range (non-zero start)", c.name)
+        }
+        if filter == "" && c.current != "" {
+            // For ident_replace, filter may be non-empty; for params, it can be empty when replacing entire segment
+        }
+        if te.NewText != c.cleaned {
+            t.Fatalf("%s: newText got %q want %q", c.name, te.NewText, c.cleaned)
+        }
+    }
+}
+