test: tighten shared join and message content coverage

src/shared/chat-message-content.test.ts

@@ -18,6 +18,19 @@ describe("shared/chat-message-content", () => {
     ).toBe("");
   });
 
+  it("only considers the first content block even if later blocks have text", () => {
+    expect(
+      extractFirstTextBlock({
+        content: [null, { text: "later" }],
+      }),
+    ).toBeUndefined();
+    expect(
+      extractFirstTextBlock({
+        content: [{ type: "image" }, { text: "later" }],
+      }),
+    ).toBeUndefined();
+  });
+
   it("returns undefined for missing, empty, or non-text content", () => {
     expect(extractFirstTextBlock(null)).toBeUndefined();
     expect(extractFirstTextBlock({ content: [] })).toBeUndefined();

src/shared/text/join-segments.test.ts

@@ -13,6 +13,8 @@ describe("concatOptionalTextSegments", () => {
   it("falls back to whichever side is present and honors custom separators", () => {
     expect(concatOptionalTextSegments({ left: "A" })).toBe("A");
     expect(concatOptionalTextSegments({ right: "B" })).toBe("B");
+    expect(concatOptionalTextSegments({ left: "", right: "B" })).toBe("B");
+    expect(concatOptionalTextSegments({ left: "" })).toBe("");
     expect(concatOptionalTextSegments({ left: "A", right: "B", separator: " | " })).toBe("A | B");
   });
 });
@@ -36,4 +38,8 @@ describe("joinPresentTextSegments", () => {
       "A | B",
     );
   });
+
+  it("preserves segment whitespace when trim is disabled", () => {
+    expect(joinPresentTextSegments(["A", "  B  "], { separator: "|" })).toBe("A|  B  ");
+  });
 });