diff --git a/test/ast_transform/line_aligned_emitter_test.rb b/test/ast_transform/line_aligned_emitter_test.rb
index 47bfb98..a3a9cb4 100644
--- a/test/ast_transform/line_aligned_emitter_test.rb
+++ b/test/ast_transform/line_aligned_emitter_test.rb
@@ -36,11 +36,13 @@ def run_as_method(emitted)
 
       emitted = emit(s(:begin, *reordered))
 
-      assert_includes emitted, '__ast_thunk_1__ = proc', emitted
-      assert_includes emitted, 'when_body', emitted
-      assert_includes emitted, '__ast_thunk_1__.call', emitted
-      # Execution order: proc defined, interaction runs, then the call.
-      assert_operator emitted.index('interaction_setup'), :<, emitted.index('__ast_thunk_1__.call'), emitted
+      # when_body stays on its source line (2) inside the proc; execution order is proc definition, interaction,
+      # then the call.
+      assert_equal <<~RUBY, emitted
+        given_setup; __ast_thunk_1__ = proc do
+        when_body; end
+        interaction_setup; __ast_thunk_1__.call
+      RUBY
     end
 
     test "thunk body statements stay on their source lines inside the proc" do
@@ -55,8 +57,12 @@ def run_as_method(emitted)
 
       emitted = emit(s(:begin, *reordered))
 
-      assert_equal 2, emitted.lines.index { |line| line.include?('when_body_first') } + 1, emitted
-      assert_equal 3, emitted.lines.index { |line| line.include?('when_body_second') } + 1, emitted
+      assert_equal <<~RUBY, emitted
+        given_setup; __ast_thunk_1__ = proc do
+        when_body_first
+        when_body_second; end
+        interaction_setup; __ast_thunk_1__.call
+      RUBY
     end
 
     test "reusing one thunk node executes its body from multiple call sites (multiplexing)" do
@@ -64,8 +70,10 @@ def run_as_method(emitted)
 
       emitted = emit(s(:begin, shared, shared))
 
-      assert_equal 1, emitted.scan('__ast_thunk_1__ = proc').size, emitted
-      assert_equal 2, emitted.scan('__ast_thunk_1__.call').size, emitted
+      # One proc, one call per occurrence — all packed onto the body's single source line.
+      assert_equal <<~RUBY, emitted
+        __ast_thunk_1__ = proc do; shared_body; end; __ast_thunk_1__.call; __ast_thunk_1__.call
+      RUBY
     end
 
     test "a thunk whose body lines fall after its execution point raises ThunkLowering::PlacementError" do
@@ -93,8 +101,9 @@ def run_as_method(emitted)
 
       emitted = emit(s(:begin, parse("real_statement\n"), synthetic))
 
-      assert_includes emitted, 'real_statement; __ast_thunk_1__ = proc', emitted
-      assert_operator emitted.index('synthetic_body'), :<, emitted.index('__ast_thunk_1__.call'), emitted
+      assert_equal <<~RUBY, emitted
+        real_statement; __ast_thunk_1__ = proc do; synthetic_body; end; __ast_thunk_1__.call
+      RUBY
     end
 
     test "distinct thunks get distinct hidden lvar names" do
@@ -103,8 +112,11 @@ def run_as_method(emitted)
 
       emitted = emit(s(:begin, first_thunk, second_thunk))
 
-      assert_includes emitted, '__ast_thunk_1__ = proc', emitted
-      assert_includes emitted, '__ast_thunk_2__ = proc', emitted
+      assert_equal(
+        '__ast_thunk_1__ = proc do; first_body; end; __ast_thunk_1__.call; ' \
+          "__ast_thunk_2__ = proc do; second_body; end; __ast_thunk_2__.call\n",
+        emitted
+      )
     end
 
     test "an unlowered custom node type raises LineAlignedEmitter::UnloweredNodeTypeError" do
@@ -128,10 +140,23 @@ def risky
         end
       HEREDOC
 
-      emitted_lines = emit(parse(source)).lines.map(&:strip)
+      # Byte-identical to the source: every keyword and statement at its line and column.
+      assert_equal source, emit(parse(source))
+    end
+
+    # A fully synthetic ensure (e.g. a transform wrapping a body in teardown, like RSpock's Cleanup) has no keyword
+    # line to target: the keyword must open a fresh line, never `;`-pack after the preceding statement.
+    test "a loc-less ensure keyword goes on a fresh line, never packed" do
+      synthetic_def = s(:def, :run, s(:args),
+        s(:ensure, s(:send, nil, :work), s(:send, nil, :cleanup)))
+
+      emitted = emit(synthetic_def)
 
-      assert_equal ['def risky', 'compute', 'rescue ArgumentError, TypeError => error', 'handle(error)',
-        'else', 'celebrate', 'ensure', 'cleanup', 'end'], emitted_lines
+      # Everything is loc-less, so it packs — except the keyword, which opens a fresh line.
+      assert_equal <<~RUBY, emitted
+        def run; work
+        ensure; cleanup; end
+      RUBY
     end
 
     test "a standalone begin/end block emits its statements at their source lines" do
@@ -142,9 +167,7 @@ def risky
         end
       HEREDOC
 
-      emitted_lines = emit(parse(source)).lines.map(&:strip)
-
-      assert_equal ['begin', 'first_call', 'second_call', 'end'], emitted_lines
+      assert_equal source, emit(parse(source))
     end
 
     test "pre-declares locals the thunk body assigns at method scope" do
@@ -153,7 +176,13 @@ def risky
 
       emitted = emit(s(:begin, *reordered))
 
-      assert_includes emitted, 'result = result; __ast_thunk_1__ = proc', emitted
+      # `result = result` registers the name at method scope before the proc; the thunked assignment stays on its
+      # source line inside it.
+      assert_equal <<~RUBY, emitted
+        given_setup; result = result; __ast_thunk_1__ = proc do
+        result = compute; end
+        interaction_setup; __ast_thunk_1__.call
+      RUBY
     end
 
     test "pre-declarations skip block-local assignments but cover the block call's arguments" do
@@ -164,18 +193,22 @@ def risky
 
       emitted = emit(s(:begin, thunk(*parse(source).children)))
 
-      assert_includes emitted, 'outer = outer', emitted
-      # width is assigned in the block call's ARGUMENTS, which evaluate at
-      # method scope; inner is first assigned inside the block, so it is
-      # block-local in the original source too.
-      assert_includes emitted, 'width = width', emitted
-      refute_includes emitted, 'inner = inner', emitted
+      # outer and width get pre-declarations: width is assigned in the block call's ARGUMENTS, which evaluate at
+      # method scope. inner does not: it is first assigned inside the block, so it was block-local in the original
+      # source too.
+      assert_equal <<~RUBY, emitted
+        outer = outer; width = width; __ast_thunk_1__ = proc do; outer = items.map { |item,|; inner = item; }
+        buffer.take(width = limit) { |line,|; sink(line); }; end; __ast_thunk_1__.call
+      RUBY
     end
 
     test "pre-declarations skip assignments inside nested defs" do
       emitted = emit(s(:begin, thunk(parse("def helper = (scoped = 1)\n"))))
 
-      refute_includes emitted, 'scoped = scoped', emitted
+      # No `scoped = scoped`: the def opens its own scope, so the assignment was never method-scope.
+      assert_equal <<~RUBY, emitted
+        __ast_thunk_1__ = proc do; def helper; scoped = 1; end; end; __ast_thunk_1__.call
+      RUBY
     end
 
     test "a thunked assignment runs late but propagates to the enclosing method scope" do
@@ -240,10 +273,8 @@ def risky
         end
       HEREDOC
 
-      emitted_lines = emit(parse(source)).lines.map(&:strip)
-
-      assert_equal 2, emitted_lines.index { |line| line.include?('first_call') } + 1, emitted_lines.join
-      assert_equal 4, emitted_lines.index { |line| line.include?('second_call') } + 1, emitted_lines.join
+      # Byte-identical to the source, blank line included.
+      assert_equal source, emit(parse(source))
     end
 
     test "a thunk composes inside expressions; its placement hoists to the enclosing sequence" do
@@ -255,11 +286,10 @@ def risky
 
       emitted = emit(s(:begin, assert_raises_call))
 
-      assert_includes emitted, '__ast_thunk_1__ = proc', emitted
-      assert_includes emitted, 'assert_raises(RuntimeError)', emitted
-      assert_includes emitted, '__ast_thunk_1__.call', emitted
       # The proc's definition precedes the assert_raises call that runs it.
-      assert_operator emitted.index('__ast_thunk_1__ = proc'), :<, emitted.index('assert_raises'), emitted
+      assert_equal <<~RUBY, emitted
+        __ast_thunk_1__ = proc do; raise_helper; end; assert_raises(RuntimeError) do; __ast_thunk_1__.call; end
+      RUBY
     end
 
     test "a thunk inside a def stays inside the def (scope boundary)" do
@@ -269,11 +299,12 @@ def risky
 
       emitted = emit(thunked_def)
 
-      # The proc and its call both sit between the def opener and its end;
-      # the body statement keeps its source line.
-      assert_operator emitted.index('def run'), :<, emitted.index('__ast_thunk_1__ = proc'), emitted
-      assert_operator emitted.index('__ast_thunk_1__.call'), :<, emitted.rindex('end'), emitted
-      assert_equal 2, emitted.lines.index { |line| line.include?('helper') } + 1, emitted
+      # The proc and its call both sit between the def opener and its end; the body statement keeps its source line.
+      assert_equal <<~RUBY, emitted
+        def run; __ast_thunk_1__ = proc do
+          helper; end; __ast_thunk_1__.call
+        end
+      RUBY
     end
   end
 end
diff --git a/test/ast_transform/line_alignment_test.rb b/test/ast_transform/line_alignment_test.rb
index 7163ad0..3363a16 100644
--- a/test/ast_transform/line_alignment_test.rb
+++ b/test/ast_transform/line_alignment_test.rb
@@ -61,20 +61,44 @@ def self.compute
     test "emission places each user statement at its source line" do
       emitted = transform_file_source(FIXTURE_SOURCE, ASTTransform::Transformation.new)
 
-      FIXTURE_LINES.each do |statement, source_line|
-        assert_equal source_line, emitted_line_number(emitted, statement),
-          "expected `#{statement}` at source line #{source_line} in:\n#{numbered(emitted)}"
-      end
+      # Statements hold lines 3, 8 and 11; the vanished comments leave blank padding, and the multi-line expression
+      # is compressed back to its first line.
+      assert_equal <<~RUBY, emitted
+        class LineAlignmentFixture
+          def self.compute
+            first_value = 1
+
+
+
+
+            second_value = first_value + 1
+
+
+            raise_helper(second_value)
+          end
+        end
+      RUBY
     end
 
     test "emission keeps user statements on their source lines when a transform injects synthetic code" do
       emitted = transform_file_source(FIXTURE_SOURCE, SetupInjectionTransformation.new)
 
-      assert_includes emitted, 'injected_setup'
-      FIXTURE_LINES.each do |statement, source_line|
-        assert_equal source_line, emitted_line_number(emitted, statement),
-          "expected `#{statement}` at source line #{source_line} in:\n#{numbered(emitted)}"
-      end
+      # The loc-less injected statement packs onto the def's line; every user statement keeps its source line.
+      assert_equal <<~RUBY, emitted
+        class LineAlignmentFixture
+          def self.compute; injected_setup
+            first_value = 1
+
+
+
+
+            second_value = first_value + 1
+
+
+            raise_helper(second_value)
+          end
+        end
+      RUBY
     end
 
     test "raw backtrace cites the source line of the raising statement, with no filtering" do
@@ -133,16 +157,6 @@ def tmp_pathname(file_name)
       Pathname.new('').join(File.expand_path(''), 'tmp', 'test', 'ast_transform', file_name)
     end
 
-    # 1-based line number of the first emitted line containing +statement+.
-    def emitted_line_number(emitted, statement)
-      index = emitted.lines.index { |line| line.include?(statement) }
-      index&.+(1)
-    end
-
-    def numbered(emitted)
-      emitted.lines.map.with_index(1) { |line, number| format('%3d| %s', number, line) }.join
-    end
-
     # All line numbers the VM records for +iseq+ and its children — the lines
     # a debugger can bind a `break file:N` to.
     def iseq_lines(iseq)
diff --git a/test/ast_transform/statement_renderer_test.rb b/test/ast_transform/statement_renderer_test.rb
index 0ce7f04..2602b25 100644
--- a/test/ast_transform/statement_renderer_test.rb
+++ b/test/ast_transform/statement_renderer_test.rb
@@ -28,7 +28,8 @@ def parse(source)
 
       rendered = StatementRenderer.for_tree(statement).aligned_render(statement)
 
-      assert_equal 1, rendered.lines.size, rendered
+      # Unparser normalizes the modifier-if to if/end; the join restores the source's single-line height.
+      assert_equal 'if strict; raise(ArgumentError); end', rendered
     end
 
     test "aligned_render keeps a render that already fits its source height" do
@@ -36,7 +37,7 @@ def parse(source)
 
       rendered = StatementRenderer.for_tree(statement).aligned_render(statement)
 
-      assert_operator rendered.lines.size, :>, 1, rendered
+      assert_equal "def risky\n  compute\nend", rendered
     end
 
     test "compress_to_single_line declines renders whose single-line join does not parse" do