test(ssd1327): Improve mock scenarios beyond smoke tests. by nedseb · Pull Request #301 · steamicc/micropython-steami-lib

nedseb · 2026-03-28T20:52:12Z

Summary

Replace "does not crash" smoke tests with behavioral assertions that verify actual I2C commands and framebuffer state.

Mock tests: from 6 to 16

Category	Test	What it verifies
Commands	Power off	`SET_FN_SELECT_A` + disable + `SET_DISP` off (exact sequence)
Commands	Power on	`SET_FN_SELECT_A` + enable + `SET_DISP` on (exact sequence)
Commands	Contrast	`SET_CONTRAST` + value byte
Commands	Invert on	`SET_DISP_MODE` = 0xA7 (inverted)
Commands	Invert off	`SET_DISP_MODE` = 0xA4 (normal)
Commands	Rotate	Exact 10-command sequence (power_off + offset + remap + power_on)
Commands	Show	Col/row address prefix + framebuffer payload size (8192 bytes)
Commands	Init display	Unlock (0xFD, 0x12) → display off (0xAE) → display on (0xAF)
Framebuffer	Pixel	Read-back verifies pixel value at (10,20)
Framebuffer	Fill	Verifies 5 corner pixels (0,0), (63,63), (127,0), (0,127), (127,127)
Framebuffer	Line	Bresenham start pixel verified at (0,0)
Framebuffer	Scroll	Pixel at (5,0) shifts to (6,0), original position cleared
Smoke	Fill black/white	Does not crash
Smoke	Text rendering	Does not crash
Smoke	Show	Does not crash

Infrastructure improvements

FrameBuffer.pixel() — read/write support for GS4_HMSB format with proper 4-bit masking
FrameBuffer.line() — Bresenham's algorithm implementation
FrameBuffer.scroll() — buffer shift with proper pixel copying

Note on I2C vs SPI

The STeaMi board uses SPI for the display. Mock tests use the I2C variant (WS_OLED_128X128_I2C) because FakeI2C provides command logging. The command sequences are identical between I2C and SPI.

Closes #261

Test plan

16 SSD1327 mock tests pass (was 6)
make ci passes (206 mock tests + 271 example validations)

Copilot

Pull request overview

Updates the SSD1327 scenario tests to assert behavioral correctness by validating the I2C command stream (instead of only “does not crash”), and enhances the FrameBuffer stub to support framebuffer state assertions.

Changes:

Replace/augment SSD1327 mock smoke tests with checks against FakeI2C write logs for power_on, power_off, contrast, invert, rotate, and show.
Add framebuffer state assertions for pixel() and fill() in SSD1327 scenarios.
Implement GS4_HMSB pixel() read/write behavior in tests/fake_machine/framebuf_stub.py.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
tests/scenarios/ssd1327.yaml	Adds mock assertions that inspect the I2C command/data stream and framebuffer state for SSD1327 behaviors.
tests/fake_machine/framebuf_stub.py	Implements GS4_HMSB `pixel()` read/write to enable framebuffer-based assertions in mock tests.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

Copilot · 2026-03-28T20:54:47Z

+            return (byte >> 4) & 0x0F if x % 2 == 0 else byte & 0x0F
+        byte = self.buffer[idx]
+        if x % 2 == 0:
+            self.buffer[idx] = (col << 4) | (byte & 0x0F)


FrameBuffer.pixel() setter path for even x writes (col << 4) without masking to 4 bits. This is inconsistent with fill() and the odd-x branch (which both mask with & 0x0F) and can raise ValueError when col > 15 because bytearray elements must be 0-255. Mask col (e.g., col &= 0x0F) before shifting/writing so the stub matches GS4 semantics.

Suggested change

self.buffer[idx] = (col << 4) | (byte & 0x0F)

self.buffer[idx] = ((col & 0x0F) << 4) | (byte & 0x0F)

Copilot · 2026-03-28T20:54:48Z

+      # power_off (3 cmds) + SET_DISP_OFFSET, 128, SET_SEG_REMAP, 0x42 + power_on (3 cmds)
+      result = 0xA2 in cmds and 0x42 in cmds and 128 in cmds


The rotate mock assertion is very loose: 0xA2 in cmds and 0x42 in cmds and 128 in cmds can pass even if the commands are in the wrong order, SET_SEG_REMAP (0xA0) is never sent, or the parameters are not associated with the right command. Since this test is meant to validate the exact I2C command sequence, consider asserting the full expected cmds list (power_off + offset + remap + power_on) in order.

Suggested change

# power_off (3 cmds) + SET_DISP_OFFSET, 128, SET_SEG_REMAP, 0x42 + power_on (3 cmds)

result = 0xA2 in cmds and 0x42 in cmds and 128 in cmds

# Expect: power_off (FN_SELECT_A disable + DISP off) +

# SET_DISP_OFFSET, 128, SET_SEG_REMAP, 0x42 +

# power_on (FN_SELECT_A enable + DISP on)

expected_cmds = [0xAB, 0x00, 0xAE, 0xA2, 128, 0xA0, 0x42, 0xAB, 0x01, 0xAF]

result = cmds == expected_cmds

Copilot · 2026-03-28T20:54:48Z

+      cmds = [data[1] for reg, data in log if reg is None and len(data) == 2 and data[0] == 0x80]
+      # SET_COL_ADDR (0x15), start, end, SET_ROW_ADDR (0x75), start, end
+      has_col = 0x15 in cmds
+      has_row = 0x75 in cmds
+      # Check data was sent (writevto with 0x40 prefix)
+      has_data = any(reg is None and len(data) > 2 and data[0] == 0x40 for reg, data in log)
+      result = has_col and has_row and has_data


The show mock test only checks that SET_COL_ADDR/SET_ROW_ADDR appear somewhere in cmds, but does not verify the start/end values or that they are sent before the data burst. This can produce false positives if the driver changes behavior but still emits those bytes. Consider asserting the exact first 6 command bytes/params (0x15, col_start, col_end, 0x75, row_start, row_end) and then validating the subsequent data write begins with 0x40 and has the expected payload length.

Suggested change

cmds = [data[1] for reg, data in log if reg is None and len(data) == 2 and data[0] == 0x80]

# SET_COL_ADDR (0x15), start, end, SET_ROW_ADDR (0x75), start, end

has_col = 0x15 in cmds

has_row = 0x75 in cmds

# Check data was sent (writevto with 0x40 prefix)

has_data = any(reg is None and len(data) > 2 and data[0] == 0x40 for reg, data in log)

result = has_col and has_row and has_data

# Collect command bytes (0x80 prefix, 1-byte payload) in order

cmd_bytes = [data[1] for reg, data in log if reg is None and len(data) == 2 and data[0] == 0x80]

# Expected: SET_COL_ADDR (0x15), col_start, col_end, SET_ROW_ADDR (0x75), row_start, row_end

# For a 128x128 SSD1327 panel, columns 0-63 (0x00-0x3F) and rows 0-127 (0x00-0x7F)

expected_prefix = [0x15, 0x00, 0x3F, 0x75, 0x00, 0x7F]

# Find first data burst (writevto with 0x40 prefix and payload > 0)

data_writes = [data for reg, data in log if reg is None and len(data) > 2 and data[0] == 0x40]

if not data_writes:

result = False

else:

first_data = data_writes[0]

# Determine expected framebuffer payload length: width * height / 2 (4-bit pixels)

width = getattr(dev, "width", 128)

height = getattr(dev, "height", 128)

expected_payload_len = (width * height) // 2

actual_payload_len = len(first_data) - 1 # exclude 0x40 prefix

result = (cmd_bytes[:6] == expected_prefix) and (actual_payload_len == expected_payload_len)

Copilot · 2026-03-28T20:54:48Z

+    action: script
+    script: |
+      dev.fill(7)
+      result = dev.framebuf.pixel(0, 0) == 7 and dev.framebuf.pixel(63, 63) == 7


Test name says "Fill sets all pixels", but the assertion only samples (0,0) and (63,63) on a 128x128 buffer. This won't catch issues in the second half of rows/columns (or the last byte in the buffer). To better match the intent, also sample an edge pixel like (127,127) (and/or (127,0)) after fill(7).

Suggested change

result = dev.framebuf.pixel(0, 0) == 7 and dev.framebuf.pixel(63, 63) == 7

result = (

dev.framebuf.pixel(0, 0) == 7 and

dev.framebuf.pixel(63, 63) == 7 and

dev.framebuf.pixel(127, 0) == 7 and

dev.framebuf.pixel(0, 127) == 7 and

dev.framebuf.pixel(127, 127) == 7

)

nedseb · 2026-03-28T20:58:31Z

Les 4 commentaires Copilot ont été corrigés dans 024057a :

pixel() masquage col — ajouté col & 0x0F avant le shift pour éviter un dépassement sur col > 15.
rotate assertion trop lâche — remplacé par une assertion stricte de la séquence complète de 10 commandes dans l'ordre exact.
show assertion insuffisante — vérifie maintenant les 6 premiers bytes de commande (col_start, col_end, row_start, row_end) et la taille exacte du payload de données (8192 bytes pour 128×128 en GS4).
fill ne teste que 2 pixels — ajouté 3 pixels supplémentaires aux coins (127,0), (0,127), (127,127).

semantic-release-updater · 2026-03-29T08:57:29Z

🎉 This PR is included in version 0.3.0 🎉

The release is available on:

v0.3.0
GitHub release

Your semantic-release bot 📦🚀

Copilot AI review requested due to automatic review settings March 28, 2026 20:52

github-actions Bot assigned nedseb Mar 28, 2026

Copilot started reviewing on behalf of nedseb March 28, 2026 20:52 View session

Copilot AI reviewed Mar 28, 2026

View reviewed changes

test(ssd1327): Improve mock scenarios beyond smoke tests.

1a99e7b

nedseb force-pushed the test/ssd1327-improve-mocks branch from aa79a97 to 1a99e7b Compare March 28, 2026 20:55

test(ssd1327): Fix Copilot review comments on mock tests.

024057a

nedseb mentioned this pull request Mar 28, 2026

test(ssd1327): Improve mock scenarios beyond smoke tests. #261

Closed

4 tasks

nedseb merged commit 8ad7a4e into main Mar 28, 2026
10 checks passed

nedseb deleted the test/ssd1327-improve-mocks branch March 28, 2026 21:00

semantic-release-updater Bot added the released label Mar 29, 2026

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

test(ssd1327): Improve mock scenarios beyond smoke tests.#301

test(ssd1327): Improve mock scenarios beyond smoke tests.#301
nedseb merged 2 commits intomainfrom
test/ssd1327-improve-mocks

nedseb commented Mar 28, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Copilot AI Mar 28, 2026

Uh oh!

Copilot AI Mar 28, 2026

Uh oh!

Copilot AI Mar 28, 2026

Uh oh!

Copilot AI Mar 28, 2026

Uh oh!

nedseb commented Mar 28, 2026

Uh oh!

Uh oh!

semantic-release-updater Bot commented Mar 29, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

	self.buffer[idx] = (col << 4) \| (byte & 0x0F)
	self.buffer[idx] = ((col & 0x0F) << 4) \| (byte & 0x0F)

		# power_off (3 cmds) + SET_DISP_OFFSET, 128, SET_SEG_REMAP, 0x42 + power_on (3 cmds)
		result = 0xA2 in cmds and 0x42 in cmds and 128 in cmds

-      # power_off (3 cmds) + SET_DISP_OFFSET, 128, SET_SEG_REMAP, 0x42 + power_on (3 cmds)
-      result = 0xA2 in cmds and 0x42 in cmds and 128 in cmds
+      # Expect: power_off (FN_SELECT_A disable + DISP off) +
+      #         SET_DISP_OFFSET, 128, SET_SEG_REMAP, 0x42 +
+      #         power_on (FN_SELECT_A enable + DISP on)
+      expected_cmds = [0xAB, 0x00, 0xAE, 0xA2, 128, 0xA0, 0x42, 0xAB, 0x01, 0xAF]
+      result = cmds == expected_cmds

-      cmds = [data[1] for reg, data in log if reg is None and len(data) == 2 and data[0] == 0x80]
-      # SET_COL_ADDR (0x15), start, end, SET_ROW_ADDR (0x75), start, end
-      has_col = 0x15 in cmds
-      has_row = 0x75 in cmds
-      # Check data was sent (writevto with 0x40 prefix)
-      has_data = any(reg is None and len(data) > 2 and data[0] == 0x40 for reg, data in log)
-      result = has_col and has_row and has_data
+      # Collect command bytes (0x80 prefix, 1-byte payload) in order
+      cmd_bytes = [data[1] for reg, data in log if reg is None and len(data) == 2 and data[0] == 0x80]
+      # Expected: SET_COL_ADDR (0x15), col_start, col_end, SET_ROW_ADDR (0x75), row_start, row_end
+      # For a 128x128 SSD1327 panel, columns 0-63 (0x00-0x3F) and rows 0-127 (0x00-0x7F)
+      expected_prefix = [0x15, 0x00, 0x3F, 0x75, 0x00, 0x7F]
+      # Find first data burst (writevto with 0x40 prefix and payload > 0)
+      data_writes = [data for reg, data in log if reg is None and len(data) > 2 and data[0] == 0x40]
+      if not data_writes:
+          result = False
+      else:
+          first_data = data_writes[0]
+          # Determine expected framebuffer payload length: width * height / 2 (4-bit pixels)
+          width = getattr(dev, "width", 128)
+          height = getattr(dev, "height", 128)
+          expected_payload_len = (width * height) // 2
+          actual_payload_len = len(first_data) - 1  # exclude 0x40 prefix
+          result = (cmd_bytes[:6] == expected_prefix) and (actual_payload_len == expected_payload_len)

-      result = dev.framebuf.pixel(0, 0) == 7 and dev.framebuf.pixel(63, 63) == 7
+      result = (
+        dev.framebuf.pixel(0, 0) == 7 and
+        dev.framebuf.pixel(63, 63) == 7 and
+        dev.framebuf.pixel(127, 0) == 7 and
+        dev.framebuf.pixel(0, 127) == 7 and
+        dev.framebuf.pixel(127, 127) == 7
+      )

Conversation

nedseb commented Mar 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Mock tests: from 6 to 16

Infrastructure improvements

Note on I2C vs SPI

Test plan

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Copilot AI Mar 28, 2026

Choose a reason for hiding this comment

Uh oh!

Copilot AI Mar 28, 2026

Choose a reason for hiding this comment

Uh oh!

Copilot AI Mar 28, 2026

Choose a reason for hiding this comment

Uh oh!

Copilot AI Mar 28, 2026

Choose a reason for hiding this comment

Uh oh!

nedseb commented Mar 28, 2026

Uh oh!

Uh oh!

semantic-release-updater Bot commented Mar 29, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

nedseb commented Mar 28, 2026 •

edited

Loading